Renowned Indian theoretical physicist Professor Deepak Dhar has been named a co-recipient of the 2026 Dirac Medal, awarded by the Abdus Salam International Centre for Theoretical Physics (ICTP) in Trieste, Italy. He has been recognised for his pioneering contributions to statistical physics, particularly his work on the Abelian Sandpile Model.

Dhar shares the award with Bernard Derrida, Marc Mézard and Haim Sompolinsky for their important contributions to statistical physics and non-equilibrium systems. He is the second scientist working in India to receive the Dirac Medal, after Ashoke Sen in 2014.

Abelian Sandpile Model

Concept and Development

Professor Deepak Dhar developed the Abelian Sandpile Model in 1990, building upon the concept of Self-Organized Criticality proposed in 1987 by Per Bak, Chao Tang and Kurt Wiesenfeld. The model explains how simple local interactions can produce complex and cascading behaviour in large systems.

In the model, sand grains are added one by one to a pile. As the pile approaches a critical state, the addition of another grain can trigger an avalanche, whose size may range from a small local event to a much larger cascade.

Abelian Property

The key contribution of Dhar was demonstrating the Abelian property, according to which the final stable configuration remains unchanged regardless of the order in which individual grains topple. This property makes it possible to mathematically analyse apparently unpredictable cascading processes.

Self-Organized Criticality

The model demonstrates Self-Organized Criticality, in which a system can naturally evolve towards a critical state. Once this state is reached, even a small disturbance can trigger events of widely different magnitudes. This provides an important framework for studying cascading behaviour in complex systems.

Applications

The concepts developed through the sandpile model have been used to understand cascading and complex behaviour in phenomena such as earthquakes, forest fires, traffic jams, neural activity and financial-market fluctuations.

Who is Professor Deepak Dhar?

Education and Academic Career

Professor Deepak Dhar was born in 1951 in Pratapgarh, Uttar Pradesh. He studied at Allahabad University, completed his master's degree at IIT Kanpur, and obtained his PhD from the California Institute of Technology (Caltech) in 1978.

During his doctoral studies at Caltech, Dhar worked as a teaching assistant to Nobel laureate Richard Feynman.

Major Awards and Recognition

Dhar received the Shanti Swarup Bhatnagar Prize in 1991, followed by the TWAS Prize in 2002 and the Padma Bhushan in 2023.

In 2022, he became the first Indian recipient of the Boltzmann Medal, the highest honour in statistical physics, sharing it with John Hopfield. With the Dirac Medal, Dhar belongs to a small group of scientists who have received both the Boltzmann Medal and the Dirac Medal.

Dirac Medal

About the Award

The Dirac Medal was instituted in 1985 by the Abdus Salam International Centre for Theoretical Physics (ICTP) in Trieste. It honours Paul A. M. Dirac, the renowned physicist and Nobel laureate who made foundational contributions to quantum mechanics.

The medal recognises scientists who have made outstanding contributions to theoretical physics and is announced annually on 8 August, the birthday of Paul Dirac.

About ICTP

The Abdus Salam International Centre for Theoretical Physics was founded in 1964 by Pakistani physicist and Nobel laureate Abdus Salam. It promotes international scientific cooperation, particularly by connecting scientists from the Global South with the wider international scientific community.

The ICTP operates under a tripartite agreement involving Italy, UNESCO and the International Atomic Energy Agency (IAEA).

Selection and Distinction

By tradition, the Dirac Medal is not awarded to individuals who have already received the Nobel Prize, Fields Medal or Wolf Prize, although some Dirac Medal recipients have subsequently received Nobel Prizes.

The Grievance Appellate Committee (GAC) is an online dispute-resolution mechanism established under Rule 3A of the Information Technology (Intermediary Guidelines and Digital Media Ethics Code) Rules, 2021, framed under the Information Technology Act, 2000. It aims to strengthen intermediary accountability and grievance redressal and promote a “Safe, Trusted and Accountable Internet” for users in India.

Core Function

The GAC hears appeals against decisions of Grievance Officers (GOs) of social media platforms and other intermediaries. The entire appeal process is conducted digitally, providing users with an additional mechanism to challenge grievance decisions.

Who Can Approach GAC?

An aggrieved user, referred to as a “Digital Nagrik”, must first approach the concerned platform’s Grievance Officer.

If the user is dissatisfied with the decision or receives no response within 30 days, an appeal can be filed before the GAC within 30 days.

Due Diligence by Intermediaries

Rule 3(1)(b)

Intermediaries are required to make reasonable efforts to ensure that users do not host, display, upload, modify, publish, transmit, store, update or share specified prohibited information.

Rule 3(2)

Intermediaries must maintain an effective grievance-redressal mechanism. Generally, grievances should be resolved within 15 days, while requests for removal of specified content should be addressed within 72 hours.

Content involving intimate imagery, sexual content, impersonation or morphed content is subject to a shorter 24-hour response requirement under Rule 3(2)(b).

Recent Context

The Delhi High Court was informed that Google had withheld a Dhruv Rathee YouTube video in India pursuant to an order of the GAC. The question of a global blocking order remained pending before a Division Bench of the High Court.

Startup India is a flagship Government of India initiative aimed at creating a startup-friendly ecosystem, encouraging innovation and entrepreneurship, generating employment and promoting sustainable economic growth. It is implemented and coordinated by the Department for Promotion of Industry and Internal Trade (DPIIT) under the Ministry of Commerce and Industry.

Definition of a Startup — DPIIT

An entity is recognised as a Startup if it is incorporated as a Private Limited Company, Partnership Firm or LLP in India, is not more than 10 years old, and has an annual turnover not exceeding ₹100 crore in any financial year. It should work towards innovation, improvement of products/services or development of a scalable business model, with potential for wealth creation or employment generation. It must not have been formed through splitting or reconstruction of an existing business.

Objectives of Startup India

The initiative seeks to promote entrepreneurship and innovation by encouraging new enterprises across sectors. It aims to create a supportive ecosystem from ideation to scaling, improve Ease of Doing Business, facilitate access to finance, generate employment and expand entrepreneurship to Tier-2, Tier-3, rural and semi-urban areas. It also promotes industry-academia collaboration, technology development and the global competitiveness of Indian startups.

Pillars of Startup India Action Plan

1. Simplification and Handholding

Startup India promotes self-certification, digital registration, simplified procedures, faster approvals and single-window mechanisms to reduce regulatory burdens. Startups are also supported through mentoring and handholding.

2. Funding Support and Incentives

The programme facilitates access to venture capital, seed funding and credit guarantees. Eligible startups can also receive various tax and fiscal incentives.

3. Industry-Academia Partnership and Incubation

Startup India encourages incubators, research parks and collaboration between universities, research institutions and industry. This helps convert research and innovation into commercial products and technologies.

Major Financial Support Mechanisms

Fund of Funds for Startups

The ₹10,000 crore Fund of Funds for Startups provides venture capital support indirectly through SEBI-registered Alternative Investment Funds, rather than directly investing in individual startups.

Startup India Seed Fund Scheme

The ₹945 crore Seed Fund Scheme supports startups at early stages, particularly for proof of concept, prototype development, product trials and market entry.

Credit Guarantee Fund

The Credit Guarantee mechanism facilitates access to collateral-free institutional credit for eligible startups.

Tax and IPR Support

Eligible startups can receive income-tax benefits, specified capital-gains exemptions and IPR-related support, including reduced fees and faster processing.

Role in Employment Generation

Startup India contributes to direct and indirect employment across technology, manufacturing, healthcare, education and services. Startups also create employment through supply chains, logistics, marketing and professional services. Their growing presence in Tier-2 and Tier-3 cities supports decentralised employment and reduces excessive dependence on metropolitan centres.

Startups further promote self-employment and first-generation entrepreneurship, while creating demand for emerging skills in areas such as Artificial Intelligence, fintech, biotechnology, renewable energy and deep technology.

Challenges Faced by Indian Startups

Regulatory Complexity

Despite improvements in the business environment, startups continue to face multiple compliance requirements at central, state and local levels.

Early-Stage Funding Gap

A major challenge is inadequate access to seed and early-stage capital, particularly for startups located outside major metropolitan centres.

Tax and Policy Uncertainty

Issues related to taxation, valuation, certification and policy changes can affect investor confidence and create uncertainty for startups.

High Failure Rate

Many startups struggle because of poor product-market fit, cash-flow problems, intense competition and lack of scalable business models.

Skill and Talent Gap

Although India has a large educated workforce, startups often face difficulty finding and retaining employees with industry-ready and specialised skills.

Way Forward

India needs to further simplify regulatory compliance, improve access to early-stage finance, strengthen incubators and research institutions, and develop an industry-oriented skilled workforce. Greater support should be provided to startups in Tier-2, Tier-3 and rural areas, while stronger assistance for international market access, technology commercialisation and global investment can help Indian startups become more competitive.

Geostrophic wind is a theoretical wind that flows parallel to isobars when the Pressure Gradient Force (PGF) is exactly balanced by the Coriolis force. It generally develops in the upper atmosphere, where the effect of surface friction is negligible.

Key Characteristics

Parallel to Isobars: The wind flows along the isobars because the PGF pulling air from high to low pressure is balanced by the Coriolis force.

Upper-Air Wind: It generally occurs above the planetary boundary layer, where surface friction becomes weak.

Role of Friction: With negligible friction, the wind can maintain a relatively steady speed and direction.

Wind Speed: Wind speed increases with a stronger pressure gradient; therefore, closely spaced isobars indicate stronger winds.

Role of Coriolis Force: The wind is deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

Latitude: It is best developed in the mid-latitudes, while it is theoretically absent at the Equator because the Coriolis parameter becomes zero.

Large-Scale System: Geostrophic winds operate over large horizontal distances and are associated with large-scale atmospheric circulation.

Isobar Pattern: Straight and parallel isobars favour geostrophic flow, whereas curved isobars produce gradient winds.

Basic Force Balance

Pressure Gradient Force ↔ Coriolis Force → Geostrophic Wind

Factors Affecting Geostrophic Wind

Pressure Gradient Force

The stronger the pressure gradient, the higher the geostrophic wind speed. Closely spaced isobars therefore indicate stronger winds.

Coriolis Force

The Coriolis force balances the pressure gradient force and determines the wind's direction relative to the isobars.

Latitude

The strength of the Coriolis force increases with latitude, making geostrophic flow more prominent away from the Equator.

Earth’s Rotation

Earth’s rotation produces the Coriolis force, which is essential for geostrophic wind formation.

Altitude and Friction

Geostrophic conditions develop where surface friction is negligible, generally in the free atmosphere above the planetary boundary layer.

Temperature Gradient

Horizontal temperature differences can strengthen upper-air pressure gradients and consequently increase wind speed.

Seasonal Winds

Seasonal winds are large-scale winds that reverse their direction with changing seasons because of differential heating of land and sea.

Formation

Unequal seasonal heating and cooling create changing pressure differences. The seasonal movement of pressure belts and the ITCZ also influences their direction and intensity.

Monsoon

The monsoon is the best-known example of seasonal winds. It produces wet summers and relatively dry winters over large regions.

Importance

Seasonal winds strongly influence rainfall, temperature, agriculture and water availability.

Local Winds

Local winds are small-scale winds produced by local differences in temperature and pressure. They are strongly influenced by surface conditions.

Characteristics

They have a limited geographical extent, are generally short-lived, and experience strong frictional influence because they occur close to the surface.

Examples

Important examples include land and sea breezes, mountain and valley winds, Loo, Chinook and Foehn.

Geostrophic vs Seasonal vs Local Winds

In State of Andhra Pradesh v. Suda Suresh Veera Venkata Naga Raju, the Supreme Court clarified that Section 187(2) of the BNSS, 2023 permits police custody to be sought in parts during the first 40 or 60 days of detention, depending on whether the applicable statutory detention period is 60 or 90 days. However, the total police custody cannot exceed 15 days.

Change from CrPC

Under Section 167 of the CrPC, 1973, police custody could generally be authorised only during the initial 15 days of remand. The BNSS has therefore expanded the time window within which police custody can be sought, while retaining the 15-day overall ceiling.

Purpose of the Extended Window

The provision allows investigators to seek police custody later within the prescribed window when fresh facts, discoveries or investigative leads emerge during investigation. Thus, there is no absolute 15-day cut-off preventing further police custody within the statutory period.

Detention under BNSS

Under Sections 58 and 187 of the BNSS, an arrested person cannot ordinarily be detained by police for more than 24 hours without Magistrate’s authorisation. Where investigation cannot be completed within this period, the Magistrate may authorise detention.

The maximum detention period is 90 days for offences punishable with death, life imprisonment or imprisonment of 10 years or more, and 60 days for other offences. After expiry of the applicable period, the accused becomes entitled to default bail, provided the statutory conditions for furnishing bail are met.

Right to Advocate — Section 38 BNSS

An arrested person has the right to meet an advocate of their choice during interrogation. However, this does not mean continuous physical presence or intervention by the lawyer throughout interrogation. The advocate may remain within sight, but cannot interfere with the investigation.

Audio-Visual Recording

The Court clarified that continuous videography of the accused's transit is not mandatory. The requirement is satisfied through audio-visual recording of the actual interrogation and discovery/recovery proceedings.

The Supreme Court has directed the 19 States and Union Territories that have not yet done so to consider declaring cancer as a notifiable disease. At present, 17 of India’s 36 States and UTs have already notified cancer.

Why is Cancer Notification Important?

The direction came in the backdrop of concerns regarding the limited coverage of the ICMR’s National Cancer Registry Programme, which reportedly covers only around 10% of India’s population, with rural coverage as low as 1%. Making cancer notifiable would ensure mandatory reporting of diagnosed cases, creating a more systematic database for surveillance, early detection, treatment planning and healthcare resource allocation.

Notifiable Disease

Meaning

A notifiable disease is a disease that is legally required to be reported to public health authorities. In India, notification is linked to public-health surveillance frameworks such as the Epidemic Diseases Act, 1897 and the Integrated Disease Surveillance Programme (IDSP), managed by the National Centre for Disease Control (NCDC).

Implications of Notification

Once a disease is declared notifiable, healthcare providers, hospitals and medical practitioners are required to report suspected, probable and confirmed cases to designated authorities. This enables governments to collect comprehensive data and monitor disease trends.

Examples

Commonly notified diseases include Tuberculosis, Dengue, Malaria, Cholera, Hepatitis, Measles, Leptospirosis and Polio. COVID-19 was declared universally notifiable during the pandemic. More recent examples include snakebite in 2024 and human rabies in 2025.

India’s Decentralised System

India does not have a single uniform national list of notifiable diseases. The power to notify diseases primarily rests with State/UT governments, resulting in variations in the diseases notified across different States and Union Territories.

International Health Regulations

The International Health Regulations (IHR), 2005, under the WHO, constitute a legally binding international framework requiring countries to notify the WHO about public-health risks or events that may have international health implications, regardless of their origin or source.

Significance for India

Declaring cancer notifiable can strengthen India’s cancer surveillance system, improve the availability of reliable epidemiological data, identify geographical and demographic patterns, support early detection, and enable better planning of cancer prevention, diagnosis, treatment and healthcare infrastructure.