Air Pollution Hazards
By Dhurjati Mukherjee
A 10-year assessment of air pollution across major urban centres has found that none of the country’s top cities met safe AQI levels at any point between 2015 and November 2025. The report, prepared by Climate Trends, analysed long-term pollution patterns across 11 major cities. The case with India is no different with its capital Delhi, as always, remaining the most polluted city throughout the period of study with average AQIA levels peaking above 250 in 2016 and hovering around 180 this year.
Cities such as Lucknow, Varanasi and Ahmedabad, which recorded high average AQI values – often above 200 – in the first half of the decade, showed some improvement in the second half. While southern and western cities such as Mumbai, Chennai, Pune and Bengaluru recorded relatively moderate AQIA levels, even they did not meet safe thresholds. A recent government report found over 2 lakh cases of acute respiratory illness in six major hospitals in Delhi though other metros such as Mumbai and Chennai find similar increases during periods of high pollution. Experts stressed the need for better planning and data-driven interventions to at least check the problem.
Referring to stubble burning which has gradually gone down in Punjab, Haryana and Rajasthan and that this happens for just a fortnight, the Supreme Court asked the Union and NCR governments to detail the measures taken on other pollution sources such as vehicles, industries, construction, dust and the tangible results through implementation of effective steps in this regard. It was very critical of construction activities and wanted quality public transport to reduce air pollution.
It is worth noting here the report of the Centre for Research on Energy & Clean Air which has rightly pointed out that, the scale of the crisis far exceeds what is generally assumed. As per the report, about 60 of India’s 749 districts breach the national annual PM2.5 standard of 40 micrograms per cubic metre that has been prescribed by the National Ambient Air Quality Standards.
Not a single district meets the far stricter guidelines of WHO, which recommends 5ug/m, about eight times more stringent than India’s standards. In fact, air pollution is an annual threat. The norther states such as Punjab, Haryana, Delhi, Himachal Pradesh and the UT of Chandigarh as well as the north-eastern state of Meghalaya maintained 100 percent district-level exceedance in all seasons except for monsoon.
The top 50 most polluted districts are mostly concentrated in four northern and eastern states – Delhi, Haryana, Punjab, Bihar and Assam. The perennial nature of poor air in the country has grave consequences for public health and this has been revealed in various studies, from time to time. Long-term exposure to PM 2.5 is associated with a range of serious diseases including stroke, lung and heart ailments.
As per a study published in The Lancet Public Health, long-term exposure to air pollution heightened mortality by 1.5 million deaths per year in the country. Despite such alarming findings, public attention and policy urgency remain disproportionately focused on metropolitan India, chiefly the national capital. Along with cities, it is imperative that Indian districts should have robust air-quality monitoring, local emission-control plans, cleaner public transport, stricter regulation of industrial and agricultural emissions, dust & waste management.
The disastrous effect of air pollution on health was investigated by scientists at the University of South California which found excess risks of death on the hottest days there are heat and extreme levels of PM 2.6. Many places in India have this combination, observed Soumya Swaminathan, the WHO’s chief scientist, while delivering the JC Bose Memorial Lecture titled ‘Fragile Futures: The Climate Crisis & Its Toll on Women and Children’.
“There are three different aspects of health risk. One is the vulnerability factor. It depends on where you live, the demography whether you are young or old, if a woman is pregnant, if someone has a medical condition, people’s socio-economic status, the gender and equity aspects and health system capacity. These are all contributing to one’s vulnerability”, stated Swaminathan.Added to this is how much a person gets exposed to these hazards and obviously the poorer sections, specially those residing in slums, slummish-type settlements and besides railway tracks are most affected.
According to the scientist, “the cardiovascular system is the first to be impacted by heat. If you have a heart condition, it can be harmful to your heart”. As such, we see heat exhaustion, dehydration and heat stroke, all of which are most severe here, she pointed out. Swaminathan also highlighted the impact of heat on mental health. People have higher risks of anxiety and stress while those with schizophrenia or depression can experience their conditions getting worse.
Some experts consider air pollution the single largest threat to human life expectancy because of its scale, reach and continuity. According to the Air Quality Life Index, it has been found that long-term exposure to current pollution levels cuts almost three-and-a-half years from an average Indian’s life. Though it is most visible during the winter months, it is active all year round. People often notice air pollution through irritation in their lungs or face breathing difficulties, but the most serious damage happens silently over the long run with exposure increasing the risk of heart disease, chronic lung disease, strokes, worsened childhood asthma, reduced life-long lung infection etc.
China and the United States have been successful in dramatically cleaning up their environment over time. Smaller nations and younger democracies like The Gambia in Africa have made meaningful progress. Other Asian countries like Japan, Thailand and Singapore have progressed as well. Ultimately, it is for India to take positive steps in this regard as clean air is a true national priority. Experts have suggested that India should work towards a more unified system like US’s Air Now and the EU’s CAMS for dedicated atmospheric monitoring with the help of air quality sensors, aviation advisories and meteorological data integrated into a single geospatial platform.
Whether the apex court’s stricture will help the state governments in implementing the graded action plan (GRAP) in scrupulously enforcing both short-term and long-term measures in tackling air pollutionremains to be seen. However, it evident that in most metros and big cities private transport rarely follows government guidelines and there is virtually very little monitoring and enforcement of pollution norms. The state governments do not want to take drastic action against these private operators as otherwise the transport system may collapse.
Thus, air degradation has become manifest throughout the year though it hits the headlines during the winter season. It goes without saying that if public health has to be safeguarded, more stringent action is called for. —INFA