A thick blanket of smog descended on New Delhi on Tuesday morning, the day after Diwali celebrations filled the night sky with fireworks. The smoke from countless firecrackers, combined with seasonal pollution and stagnant weather conditions, caused air quality in India’s capital to deteriorate to hazardous levels.

Residents across the city woke to a grey haze that reduced visibility and left the air heavy with the acrid smell of smoke. Data from monitoring stations showed the Air Quality Index (AQI) exceeding 350 in many neighbourhoods — a level classified as “severe” and considered dangerous to breathe by international standards. The World Health Organization’s recommended daily limit for safe air quality was surpassed several times over.

By morning, the city’s skyline had nearly disappeared under the haze. Iconic landmarks such as India Gate and the Red Fort stood shrouded in thick smog, while commuters navigated through low visibility on major roads. Many residents reported irritation in the eyes and throat, and public health experts warned of potential spikes in respiratory and cardiac ailments over the coming days.

Firecracker Bans Ignored Despite Restrictions

The latest pollution surge followed a weekend of widespread Diwali celebrations, during which fireworks lit up the sky across the national capital and its surrounding regions. Despite restrictions, people burst crackers late into the night on Monday, adding millions of tonnes of fine particulate matter to the already polluted air.

India’s Supreme Court had recently relaxed the blanket ban on firecrackers, allowing the limited use of “green firecrackers” — a cleaner alternative developed by government research institutions to reduce emissions by around 30 percent. The court had also restricted their use to specific time windows during the festival period. However, as in previous years, enforcement remained weak, and most areas of the city saw widespread violation of the rules.

The Delhi-National Capital Region (NCR), home to over 30 million people, consistently ranks among the most polluted urban areas in the world, particularly in winter. The annual air quality crisis is fueled by a combination of factors — festive fireworks, vehicular emissions, industrial pollution, and the seasonal burning of agricultural residue in neighbouring states such as Punjab and Haryana. Cooler temperatures and low wind speeds during the season trap these pollutants near the ground, turning the region into a gas chamber.

Emergency Measures and Long-Term Challenges

Authorities in Delhi have announced a series of short-term interventions aimed at reducing pollution levels. Construction and demolition activities have been curtailed, the use of diesel generators restricted, and traffic regulations tightened under the Graded Response Action Plan (GRAP). Schools have also been advised to limit outdoor activities for children.

However, environmental experts warn that these reactive measures are not enough. Long-term strategies — including a transition to cleaner energy, stricter emission standards for vehicles, and greater investment in public transport — are essential to break the cycle of pollution that grips the city each year. They emphasize that public awareness and compliance with pollution control laws remain crucial to making any meaningful progress.

Pollution’s Wider Impact: Declining Sunshine Across India

Adding to the concern, a recent scientific study has linked rising air pollution to a reduction in sunshine hours across India. Published in Scientific Reports, a journal by Nature Portfolio, the study found that increased levels of aerosols — fine particles from vehicles, industrial emissions, and biomass burning — have steadily reduced the amount of sunlight reaching the Earth’s surface.

The research highlighted northern India, including the Indo-Gangetic Plain, as one of the most affected regions. The decline in sunshine, scientists say, could have serious implications for solar energy production and agricultural yields, as well as broader environmental and health effects.

Reduced sunlight means lower efficiency for solar power projects, a key component of India’s renewable energy transition. It also affects plant growth and crop productivity, threatening food security in the long run.

A Recurring Urban Health Emergency

As New Delhi grapples with its post-Diwali haze, the episode serves as a stark reminder of the city’s ongoing struggle with air pollution. Despite periodic crackdowns and public campaigns, the convergence of festival emissions, weather conditions, and chronic pollution sources continues to create a yearly public health emergency.

With winter just beginning, experts caution that air quality may worsen further in the coming weeks unless sustained and coordinated action is taken. The smog over New Delhi is more than just an annual inconvenience — it is a warning sign of the urgent need for cleaner air and stronger environmental governance.