With Delhi recording air pollution levels seven to eight times above safe standards on Monday, the city government announced the return of its flagship odd-even scheme after four years anticipating further deterioration of air quality post-Diwali.
To protect the health of schoolchildren, the government also decided to suspend in-person classes in all schools, except for students in grades X and XII preparing for board exams, until November 10.
The city's 24-hour average Air Quality Index (AQI), recorded at 4 pm daily, stood at 421 on Monday, a marginal improvement from 454 on Sunday, even as a toxic haze persisted over the city for the seventh consecutive day.
Several cities in neighbouring Haryana, Rajasthan, and Uttar Pradesh have also reported hazardous air quality. Neighbouring Ghaziabad (391), Gurugram (373), Noida (384), Greater Noida (420), and Faridabad (412) also reported hazardous air quality.
The concentration of PM2.5, fine particulate matter capable of penetrating deep into the respiratory system and triggering health problems, exceeded the government-prescribed safe limit of 60 microgrammes per cubic metre by seven to eight times at multiple locations throughout Delhi-NCR.
It was 30 to 40 times the healthy limit of 15 microgrammes per cubic metre set by the World Health Organization (WHO).
According to the ministry of earth sciences' Air Quality Early Warning System for Delhi-NCR, the region is likely to experience severe air quality for another five to six days.
Breathing in the polluted air of Delhi is equivalent to the harmful effects of smoking approximately 10 cigarettes a day, said Rajesh Chawla, senior consultant in pulmonology and critical care at Indraprastha Apollo Hospital.
The doctor said prolonged exposure to high levels of pollution can cause or exacerbate respiratory problems such as asthma, bronchitis, and chronic obstructive pulmonary disease (COPD) and can dramatically raise the risk of cardiovascular disease.
Anticipating a spike in air pollution levels post-Diwali, Delhi Environment Minister Gopal Rai announced the return of the odd-even scheme, under which cars are allowed to operate on alternate days based on their odd or even number plates.
He also said a decision on allowing 50 per cent of staff in government and private offices to work from home will be made after Diwali.
Rai said directives have been issued to implement the stringent restrictions mandated under the final stage of the Central government's air pollution control plan for Delhi-NCR, called the Graded Response Action Plan (GRAP).
The restrictions under stage IV of GRAP, including a ban on all kinds of construction work and the entry of polluting trucks into the capital, took effect on Sunday after air quality in the capital dropped to "severe plus" (AQI above 450) levels.
GRAP categorises actions into four stages: Stage I - 'Poor' (AQI 201-300); Stage II - 'Very Poor' (AQI 301-400); Stage III - 'Severe' (AQI 401-450); and Stage IV - 'Severe Plus' (AQI >450).
Earlier on Monday, Delhi Chief Minister Arvind Kejriwal held a meeting with senior officials of his government to review the implementation of an action plan to control air pollution in winter.
Unfavourable meteorological conditions, combined with vehicular emissions, paddy straw burning, firecrackers, and other local pollution sources, contribute to hazardous air quality levels in Delhi-NCR during the winter every year.
According to a Delhi Pollution Control Committee (DPCC) analysis, the capital experiences peak pollution from November 1 to November 15 when the number of stubble-burning incidents in Punjab and Haryana increases.
The New Delhi-based Indian Agricultural Research Institute (IARI) said a total of 4,160 farm fires were reported from North India on Sunday -- the highest so far this season.
Punjab alone reported 3,230 incidents of stubble burning, the state's highest in a day so far this season, according to Punjab Remote Sensing Centre data.
Under Stage IV of GRAP, only CNG, electric, and BS VI-compliant vehicles from other states are allowed to enter Delhi. Exemptions are granted only to those involved in essential services.
All medium and heavy goods vehicles not engaged in essential services are also banned in the capital, according to the latest CAQM order.
Air quality in Delhi-NCR declined over the last 10 days due to a gradual drop in temperatures, calm winds that trap pollution, and a surge in post-harvest paddy straw burning across Punjab and Haryana.
Data from the Central Pollution Control Board (CPCB) shows that Delhi's AQI increased by over 200 points between October 27 and November 3, ending up in the 'severe plus' category on Friday.
Friday's 24-hour average AQI (468) was the worst since the previous high of 471 recorded on November 12, 2021.
While the capital is grappling with an air crisis, a first-of-its-kind study launched by the Delhi government to help identify different sources of pollution in the city and accordingly take mitigating action was recently halted on the orders of Delhi Pollution Control Committee Chairman Ashwani Kumar, Rai alleged.
Kumar also "unilaterally" ordered a halt to the operation of a large smog tower installed at Connaught Place two years ago to mitigate air pollution in the area, according to Rai.
Delhi's air quality ranks among the worst in the world's capital cities.
A report by the Energy Policy Institute at the University of Chicago (EPIC) in August said that air pollution is shortening lives by almost 12 years in Delhi.
