Toxic air pollution surges in Indian capital

New Delhi’s pollution surge was extreme. Air monitors recorded PM2.5 levels above 461 micrograms per cubic meter in parts of the city. The article reports that this was more than 30 times the World Health Organization’s recommended daily limit. That comparison places the reading far beyond the level considered safe for daily exposure.

The measurement concerns PM2.5, tiny particles that can enter the bloodstream. Such high readings matter because residents across the capital and its wider metropolitan area are breathing polluted air. More than 30 million people live in the wider metropolis, increasing the number potentially exposed.

The spike came despite tighter measures introduced three days earlier. Authorities restricted traffic and construction to curb smog. Pollution is expected to worsen before Diwali, when fireworks may add more emissions. The reading demonstrates that short-term controls have not yet overcome the city’s many pollution sources.

PM2.5 refers to extremely small particles suspended in the air. The article describes them as cancer-causing microparticles. Their importance comes from their size: they are small enough to pass through the lungs’ defenses and enter the bloodstream. This makes them more than a visible layer of smog.

In New Delhi, PM2.5 levels rose above 461 micrograms per cubic meter in parts of the city. The particles can come directly from sources such as vehicles, biomass burning, industry, and coal-fired power plants. They can also form later in the atmosphere when gases react.

The danger grows when high concentrations persist. A 2024 study estimated that air pollution was linked to 3.8 million deaths in India between 2009 and 2019. The article therefore presents PM2.5 as both a microscopic pollutant and a major public-health concern.

Pollution is expected to worsen during Diwali because firework displays add emissions to air that is already heavily polluted. The festival of lights takes place on Sunday in the article’s timeline. This creates a seasonal pressure point for a city already struggling with severe smog.

The Supreme Court allowed limited use of so-called green firecrackers. These are designed to reduce emissions, but the restriction does not eliminate fireworks. The article also reports that restrictions are routinely flouted, and explosions reverberate through the city.

That combination makes the outlook especially concerning. New Delhi had already recorded PM2.5 levels above 461 micrograms per cubic meter in parts of the city. Authorities had tightened traffic and construction measures, but fireworks could add another burst of pollution. The expected worsening shows how festival activity can compound existing urban and regional emissions.

Delhi’s winter pollution comes from several sources, with secondary particles providing the largest share at 27%. Vehicles contribute 23%, while biomass burning, including farm stubble fires, contributes 20%. Industry, including coal-fired power plants, accounts for about 9%.

These figures show that pollution is not caused by one activity alone. Traffic is a major source, but smoke from burning biomass and emissions from industry also matter. Secondary particles are especially important because they form when gases from several sources react in the atmosphere. Fertilizer use can help fuel that process.

The source shares also explain why authorities use several controls at once. They tightened restrictions on traffic and construction, but those steps cannot directly remove every source. Farm fires, industrial emissions, atmospheric reactions, and later fireworks all add pressure. The article’s figures point to a problem spread across transport, agriculture, energy, and atmospheric chemistry.

Prolonged exposure to PM2.5 can produce serious health consequences because these particles are cancer-causing and small enough to enter the bloodstream. The article does not list every illness or symptom. It does show that exposure is associated with a large national health burden.

The scale is stark in India. A 2024 study in The Lancet Planetary Health estimated that 3.8 million deaths between 2009 and 2019 were linked to air pollution. That figure covers air pollution broadly, rather than PM2.5 alone, so it should not be treated as a count of deaths caused only by these particles.

New Delhi’s readings make the concern immediate. PM2.5 exceeded 461 micrograms per cubic meter in parts of the city. With more than 30 million people in the wider metropolis, severe pollution can expose a very large population. The article’s evidence connects dirty air with both bodily penetration and major mortality.

Secondary particles are not necessarily emitted as finished particles. Instead, they form in the atmosphere after gases released by pollution sources react with one another. The article identifies vehicles, industry, power plants, and biomass burning as sources of those gases.

For example, emissions from traffic, a coal-fired power plant, or a farm stubble fire can enter the air as gases. Atmospheric reactions then transform some of those gases into secondary particulate matter. The resulting particles contribute 27% of Delhi’s winter pollution, the largest share listed in the article.

This chemistry makes pollution harder to control through one measure. Reducing traffic may lower some emissions, but other sources can still supply gases for particle formation. Fertilizer use can add ammonia, which reacts with other pollutants and helps create more particulate matter. Thus, pollution can grow after emissions enter the atmosphere.

Fertilizer can worsen air pollution by releasing ammonia into the atmosphere. Ammonia is a gas, but it can react with other pollutants in the air. Those reactions produce secondary particulate matter, adding pollution that was not emitted as particles directly.

Jacob Koshy explains that the large quantity of ammonia released from fields around the capital creates a “base layer” for other pollutants to react with. In this way, fertilizer use helps the atmosphere convert emissions from vehicles, industry, power plants, and biomass burning into additional particles.

The article identifies secondary particles as Delhi’s largest reported winter-pollution source, at 27%. That means controlling visible sources alone may not address the whole problem. Pollution policy also needs to account for what happens after gases are released. Fertilizer use around the capital is presented as one factor that fuels those atmospheric reactions.