delhi

Updated: Nov 20, 2019 08:51 IST

After three days of relief, Delhi’s air quality on Wednesday once again dropped to the ‘very poor’ category, with the air quality index (AQI) recorded at 313 at 8 am by the Central Pollution Control Board (CPCB).

Monitoring agencies had earlier warned that the pollution levels are likely to spike from Wednesday as the wind speed is expected to slow down and cloud cover is likely to return. The cloud cover may block sunlight and allow little ventilation, pushing up the pollution levels over the next two days, they said.

Last week, Delhi had witnessed an air pollution ‘emergency’ with air quality dropping to severe levels, which led the city government to direct schools to temporarily shut down. Blanket bans were also imposed on construction and industrial activities, until further notice, by a Supreme Court-appointed pollution control authority.

The air quality had improved to ‘very poor’ category on November 16 and further to ‘poor’ category on November 17. Since then, it remained in ‘poor’ category until Wednesday.

An AQI between 0 and 50 is considered ‘good’, 51 and 100 ‘satisfactory’, 101 and 200 ‘moderate’, 201 and 300 ‘poor’, 301 and 400 ‘very poor’, and 401 and 500 ‘severe’.

On Tuesday, the levels of PM 2.5 — the most harmful aerosols in Delhi’s air — were recorded at 95ug/m3 at 8am, which rose to 122ug/m3 at 7pm, as per the central pollution control board.

One of the major reasons for the national capital’s poor air quality is the incidence of stubble burning by farmers in neighbouring Punjab and Haryana.

The issue was also raised in the parliament. The lawmakers called for urgent new steps on Tuesday to tackle air pollution, holding an unprecedented discussion that also exposed political fault-lines at a time when concerted, interstate efforts seem to be the only way out of a crisis that has defied a raft of mechanisms put in place in recent years.