India’s capital accused of manipulating air quality readings

Critics say alleged bid to artificially lower readings gives false impression that city’s anti-pollution drive is working

- Debarshi Dasgupta India Correspondent

October arrives each year in India’s capital with its notorious toxic smog, blanketing the city’s skyline and sending its residents into coughing fits.

It is no different in 2025, but there is a new worrying development: Another “smog” is hovering over the veracity of New Delhi’s pollution readings, denting the credibility of its data and potentially impairing the fight against pollution.

The Delhi government has been accused of spraying water around air-quality monitoring stations to lower dire readings and even switching them off during key pollution periods ~ for example, when a litany of firecrackers increased the pollution load during Diwali in October.

India’s Air Quality Index (AQI) classifies pollution as “severe” — the sixth and worst level - when readings are between 400 and 500. A “good” air reading, on the other hand, ranges from 0 to 50.

Critics say artificially lowered pollution readings give a false impression that the city’s campaign against pollution is working effectively, masking the government’s failure in curbing the menace.

“It’s almost like there’s no political will (to tackle pollution) at the end of the day,’ Mr Vimlendu Jha, an environmentalist based in Delhi, told The Straits Times at a protest on Nov18 in the city against its rising pollution levels. “Perhaps it’s better and easier to manage perception than pollution,” he added.

ST witnessed what appeared to be an attempted data manipulation at the pollution monitoring station in Delhi's Jahangirpuri neighbourhood on Nov 21.

A sprinkler truck was making repeated rounds of the leafy Industrial Training Institute (ITI) campus that houses the monitoring equipment, spraying water not just around it but even in its direction.

Students, meanwhile, played badminton on the damp grounds during their lunch break.