Delhi pollution: What the AQI shows, what GRAP Stage I requires, what readings differ

What the AQI shows: 245 on October 21, the first poor reading of the season, up from 179 a day earlier.

What GRAP Stage I requires: dust control, restrictions on diesel generators and tandoor coal, and a ban on non-compliant interstate buses.

What causes it: cold nights, light winds, firecrackers and farm fire smoke, according to experts quoted.

Discrepancy: reports give 244 or 245 for Wednesday and 226 or 233 for Thursday.

Outlook: forecasts say the air will stay poor.

The index had been 179 the previous day, according to Outlook India.

It was 227 at 7 am, 245 at 4 pm on the Central Pollution Control Board’s 24-hour average, and 248 by 8 pm, according to the same report.

Outlook India says the city had its most polluted day after Dussehra in five years, and the last higher post-festival reading was 284 in 2021.

Seven stations recorded very poor air, led by Pusa at 329 and Chandni Chowk at 326, according to Outlook India.

The Commission for Air Quality Management invoked Stage I of the Graded Response Action Plan, according to the reports.

Agencies across the National Capital Region are to implement, monitor and review the measures to prevent further deterioration, according to Outlook India.

Stage I applies when the AQI is between 201 and 300, and Stage II applies between 301 and 400, according to a report on the plan.

Stage I focuses on dust and waste, with road cleaning, water sprinkling, construction dust control and action against open waste burning, according to NewsDrum and Aryan Age.

Coal use in hotel and restaurant tandoors is restricted, and diesel generators are permitted only in emergencies, according to the reports.

Entry of intercity and interstate buses from several northern states is banned if they do not meet BS-VI norms and do not run on electricity or compressed natural gas, according to Outlook India.

Air pollution in Delhi (file image), Wikimedia Commons, CC BY-SA 4.0