We don’t think, so we can’t breathe

Core causes of India’s air pollution crisis have been clear for 25 years: burning of biomass and coal.
Still, the bickering continues. And the Delhi problem spreads to Mumbai, Bengaluru, Hyderabad

Every winter, Delhi’s air pollution debate follows a familiar script. We look for villains, argue over blame, ignore science and solutions. This year has been no different – except that it has bordered on the absurd.
Pollution season opened with the Supreme Court allowing “green crackers”, followed by Delhi govt’s failed cloud-seeding experiment. Soon after came official data claiming a 90% reduction in stubble burning in Punjab and Haryana. Overnight, stubble burning was declared “not a problem”. Even though scientific evidence told a very different story.

A paper from ISRO and an independent analysis by my colleagues showed that stubble burning continued widely across Punjab. Haryana, UP, and MP, significantly contributing to pollution in Delhi-NCR. Real issue was not theabsence of fires, but the failure of monitoring. Govt agencies rely largely on polar-orbiting satellites that pass over India in the early after- noon. As farmers simply shift the burning to late afternoon and evening, a large proportion of farm fires is no longer being detected.

Instead of fixing the monitoring system, we wasted weeks in tu-tu main-main over whether stubble burning or Delhi’s local sources were to blame. Lost in this noise was a far more important question: how prepared were institutions such as MCD. Delhi Pollution Control Committee, and Commission for Air Quality Management for the pollution season? As usual, we forgot to demand real solutions or hold institutions accountable.

All this is particularly frustrating because the core causes of India’s air pollution crisis have been known for at least 25 years. In 1999, more than 200 scientists from across the world participated in the Indian Ocean Experiment, led by the renowned atmospheric scientist V Ramanathan. Thisstudy identified a massive brown haze which they called the “Asian Brown Cloud” – stretching over the Indian subcontinent and the Indian Ocean from Oct to Feb.

Their findings were unequivocal. This haze was largely caused by the burning of biomass in homes and fields, and fossil fuels (especially coal) in industry and power plants. Pollution travelled thousands of kms, altered rainfall patterns, reduced agri productivity, and caused widespread respiratory and cardiovascular disease

When UNEP published the findings in 2002, some prominent Indian scientists questioned the terminology and intent. The phenomenon was renamed the “Atmospheric Brown Cloud with a focus on Asia”, while the warnings were largely ignored by govts.

A quarter century later, air pollution has become a pan-India crisis. Cities such as Mumbai, Bengaluru, and Hyderabad, which once had relatively clean air, now routinely fail to meet national air quality standards. This deterioration is not accidental. It is the direct result of our persistent failure to address the primary sources of pollution identified decades ago.

What pollutes India? | Over the last five years, Indian scientific institutions have produceda growing body of research that policymakers have largely ignored. A 2024 study involving researchers from prominent institutions, including earth sciences ministry found that about 50% of PM10 and PM2.5 in Delhi during the peak pollution season comes from biomass-burning sources. Another study from IIT-Kanpur, published in 2023, showed that biomass burning (especially residential heating) is the main driver of intense and frequent night-time haze in Delhi during Janand Feb.
Similar findings have emerged from other parts of the country Together, they point to a clear conclusion: open burning of biomass (whether for cooking and heating in homes, in small industrial and commercial establishments, or in agricultural fields) is the single largest source of air pollution in India. Without sharply reducing biomass burning, we simply cannot clean the country’s air.

The second major source of pollution is coal use in industries and power plants. A 2023 study by my colleagues estimated that around 37% of India’s PM2.5 emissions come from industry and power generation. Vehicular pollution is the third largest source, especially in cities.
Basically, what we burn the most, pollutes the most. India burns around 220cr tonnes of fuel and waste every year. About 85% of this iscoal and biomass; petrol, diesel and gas together account for only 15%. Unsurprisingly, most of our pollution comes from coal and biomass. Add dust from roads, construction sites and barren land, and the picture becomes even clearer.

No short-cuts | Solving India’s air pollution crisis requires a clean energy transition and an “all-of-the-above” approach.

• Biggest gains will come from the residential sector. Transitioning households to LPG, biogas or electricity for cooking and heating would eliminate a large share of PM2.5 emissions and prevent nearly 800,000 premature deaths each year from indoor air pollution. This is difficult, but achievable through targeted policies such as a strengthened PM Ujjwala programme that provides adequate incentives for low-income households to abandon biomass completely
• Industry must be the next priority Encouraging MSMEs to adopt cleaner fuels and technologies, such as electric boilers and furnaces, combined with strict monitoring, can substantially Teduce emissions. For large industries and power plants, enforcementof strict emission standards must be non-negotiable.
• Eliminating stubble burning remains essential to reducing severe pollution episodes in Oct and Nov. In just 45 days, stubble burning emits as much PM2.5 as all vehicles in India do in an entire year. The solutions- technology, market access, incentives, penalties – are well-known and proven.
• Scaling up electric vehicles and public transport will steadily reduce urban pollution, but this requires ambitious targets and serious investment, not slogans. Finally, local sources (dust, construction, garbage burning, congestion) must be tackled by empowered and accountable urban local bodies.

Real progress on the above action plan will only begin when we stop bickering over science. So, acknowledging the true impact and sources of our pollution crisis is the first step towards meaningful action.