In a modest improvement, Delhi experienced a slight amelioration in air quality overnight due to an increase in the wind speed and a change in the wind direction, the Commission for Air Quality Management in National Capital Region and Adjoining Areas (CAQM) on Saturday removed stringent curbs, including a ban on construction work related to linear projects and the entry of polluting trucks and commercial four-wheelers into the national capital. The city's 24-hour average AQI, recorded at 4 pm every day, improved from 405 on Friday to 319 on Saturday. Neighbouring Ghaziabad (276), Gurugram (322), Greater Noida (228), Noida (265) and Faridabad (309) also recorded "very poor" air quality.
These measures constitute the final stage, Stage IV, of the Centre's air pollution control plan, which is activated at least three days before the Air Quality Index (AQI) surpasses the 450-mark in the capital.
The CAQM has asked Delhi and NCR states to revoke all emergency measures, which allow only CNG, electric and BS VI-compliant vehicles from other states to enter Delhi, with exemptions granted to those involved in essential services. All medium and heavy goods vehicles not engaged in essential services were also banned in the capital under Stage IV of GRAP, according to the latest CAQM order.
The air quality forecasts by the India Meteorological Department/Indian Institute of Tropical Meteorology do not indicate any steep degradation in the overall air quality of Delhi-NCR in the coming days, the CAQM said. An official at the India Meteorological Department (IMD) said an improvement in the wind speed from November 21 onwards might bring the air pollution levels down.
The AQI was 401 on Wednesday, 397 on Tuesday, 358 on Monday, 218 on Sunday, 220 on Saturday and 279 on Friday.
The relatively better air quality last weekend was attributed to rain. Air pollution levels surged in the following days due to intense firecracker bursting on Diwali night and a resurgence in stubble burning in the neighbouring states.
Recent findings from a joint project by the Delhi government and Indian Institute of Technology (IIT), Kanpur found out that vehicular emissions accounted for about 45 per cent of the capital's air pollution on Friday. This reduced to 33 per cent on Saturday.
Secondary inorganic aerosols -- particles such as sulfate and nitrate that are formed in the atmosphere due to the interaction of gases and particulate pollutants from sources like power plants, refineries and vehicles -- is the second major contributor to Delhi's foul air, accounting for 19 to 36 per cent of the air pollution in the city over the last few days.
Delhi's air quality dropped over the last few days despite the city government implementing stringent measures, including a ban on construction work and the entry of diesel-guzzling trucks into the national capital.
According to IQAir, a Swiss company that specialises in air-quality monitoring, Delhi was the second-most polluted city in the world on Saturday after Baghdad.
The Delhi government set up a six-member special task force (STF) on Thursday to ensure a strict implementation of the measures outlined in the GRAP in the capital. Delhi's special secretary (environment) will head the STF, whose members include senior officials from the departments of transport, traffic, revenue, Municipal Corporation of Delhi (MCD) and Public Works Department (PWD). According to IQAir, a Swiss company that specialises in air-quality monitoring, Delhi was the second-most polluted city in the world on Saturday after Baghdad.
Doctors say breathing in the polluted air of Delhi is equivalent to the harmful effects of smoking approximately 10 cigarettes a day.
