Delhi’s 24-hour average air quality index (AQI), which was 379 at 4 pm, broke the 400 mark at 10 pm amid extremely calm air conditions and the formation of an inversion layer, which adversely affects vertical mixing aloft. in which pollutants can spread.
The decision to impose Phase 4 curbs came hours after the Commission for Air Quality Management (CAQM) imposed restrictive measures under GRAP Phase 3, after Delhi’s AQI breached 350 marks in the afternoon.
As per the revised GRAP schedule, classes VI-IX and XI should be conducted in hybrid mode (physical and online) under class 4 phase in Delhi, Gurugram, Faridabad, Ghaziabad and Gautam Buddha Nagar.
The fourth phase includes a ban on all construction and demolition activities, including public projects such as highways, flyovers, power lines and pipelines. Non-essential diesel trucks are prohibited from entering Delhi.
Public, municipal and private offices should decide to allow only 50 percent of employees to work in the office and the rest of the employees to work from home. States may consider additional measures such as closing colleges, non-essential businesses and imposing heavy vehicle bans.
Under Stage 3, imposed earlier in the day, the use of BS-III petrol and BS-IV diesel cars (4-wheelers) is restricted in Delhi and nearby NCR districts. Disabled persons are exempted. Stage 3 also bans non-essential diesel-powered medium goods vehicles of BS-IV or older norms in Delhi.
The state governments of Delhi and NCR have been asked to fix timings for public and municipal offices under Stage 3. The Center may consider similar measures for its offices in Delhi-NCR.
During winters, Delhi imposes restrictions under GRAP, which categorizes air quality 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 above 450).
GRAP 4 was invoked in Delhi for the first time this season in November due to persistently high pollution levels in the city and adjoining areas.
The Supreme Court allowed the CAQM to relax the curbs in the first week of December after the city’s air quality improved.
Adverse weather conditions combined with vehicular emissions, paddy-straw burning, firecrackers and other local pollution sources lead to dangerous air quality levels in Delhi-NCR during winter.
Breathing Delhi’s polluted air is equivalent to smoking about 10 cigarettes a day, say doctors.
Prolonged exposure to high pollution levels can increase respiratory problems like asthma, bronchitis and chronic obstructive pulmonary disease (COPD) and significantly increase the risk of heart diseases, according to doctors.