Delhi air quality: Key numbers

AQI on October 20: 179.

AQI on October 21: 245 (first poor reading this season).

Highest stations: Pusa 329 and Chandni Chowk 326.

GRAP stage invoked: Stage I.

Stubble burning share on Wednesday: 3.9% of PM2.5.

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.

Public transport has been expanded, including extra CNG and electric buses, and the Delhi Metro added 20 weekday trips from Thursday, according to the same report.

Delhi Traffic Police urged commuters to use public transport or carpool and reminded motorists to keep valid Pollution Under Control certificates.

Skymet’s Mahesh Palawat cited falling night temperatures and light winds, which trap traffic, industrial and dust emissions, according to Outlook India.

Envirocatalyst’s Sunil Dahiya pointed to slow north-westerly winds carrying farm fire smoke and festive emissions, according to the same report.

Firecrackers and Ravana effigy burning on Dussehra contributed, according to Outlook India.

Stubble burning contributed an estimated 3.9% of Delhi’s PM2.5 on Wednesday, and the Decision Support System projects 7.4% on Thursday, 15.9% on Friday and 4.1% on Saturday, according to the report.

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