Air quality in 34 Indian cities is in the 'very poor' category.
Air pollution in Delhi is at its highest since January, with some areas in the National Capital Region reporting "severe" category air quality. According to the latest forecast, it's set to worsen and remain in the "very poor" category over the next three days, which can trigger health advisories.
The Air Quality Index at Anand Vihar in Delhi was 455 at 4 pm, making it one of the most polluted areas here.
At 5 pm, Delhi had an overall AQI of 357, Ghaziabad 384, Noida 371, Greater Noida 364, and Faridabad 346.
Not just Delhi, from Punjab to Uttar Pradesh and Bihar, air quality in 34 Indian cities is in the 'very poor' category.
An AQI between zero 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'.
Experts say the deterioration in the quality of air is because of the wind direction and wind speed, which is causing the accumulation of pollutants coupled with an increase in incidents of farm fires.
Pollution around Diwali was the lowest in 7 years, as the weather conditions were a game changer. The air quality in the national capital started deteriorating from October 24 with the AQI slipping to the 'very poor' category from 'poor'.
Pollution levels crept up on the night of October 23 amid a drop in temperature and wind speed, and due to people lighting firecrackers and a rise in the number of farm fires.
Pollutants will continue to come in from Punjab and Haryana, and the wind will be extremely calm, thus the pollutants will remain suspended for longer.
On October 19, the subcommittee of the Commission for Air Quality Management (CAQM) had implemented Stage II of the Graded Response Action Plan (GRAP) - a set of anti-air pollution measures followed in Delhi and its vicinity according to the severity of the situation in the capital.
GRAP's Stage II includes banning the use of coal and firewood in hotels, restaurants and open eateries. The use of diesel generators, except for essential services, is also banned.
GRAP is classified under four stages depending on the air quality in Delhi. Stage I in a case of 'poor' air quality (AQI 201-300), Stage II for 'very poor' air quality, Stage III for 'severe' air quality (AQI 401-450), and Stage IV for 'severe plus' air quality (AQI>450).
If the situation turns 'severe' (Stage III), authorities will enforce a ban on construction and demolition activities in NCR, except for essential projects (such as railways, metros, airports, ISBTs and national security/defence-related projects of national importance).
Brick kilns, hot mix plants and stone crushers not operating on clean fuels, and mining and associated activities in NCR will also be banned under Stage III.
The state governments in Delhi-NCR may also impose restrictions on BS-III petrol and BS-IV diesel light motor vehicles (four-wheelers) under Stage III.