Delhi AQI improves marginally to 413; haze persists, health concerns rise

Pollution levels in the national capital and its surrounding areas dipped marginally overnight due to a relatively better wind speed. Delhi's air quality index (AQI) marginally improved from 468 at 4 p.m. on Friday to 413 at 6 a.m. on Saturday. 

However, the concentration of poisonous PM2.5 was still more than 80 times the healthy limit prescribed by the World Health Organization (WHO). 

Friday's 24-hour average AQI (468) was the worst since the previous high of 471 recorded on November 12, 2021.

A thick toxic haze lingers over the city for the fifth consecutive day on Saturday, with doctors expressing concerns that air pollution is causing an increase in respiratory and eye problems among children and the elderly.

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 micrograms per cubic metre by seven to eight times at multiple locations throughout Delhi-NCR.

It was 80 to 100 times the healthy limit (5 micrograms per cubic metre) set by the World Health Organization (WHO).

The air quality in Delhi-NCR declined over the past week 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.

According to the data from the Central Pollution Control Board (CPCB), Delhi's AQI increased by more than 200 points between October 27 and November 3, culminating in a descent into the "severe plus" category (above 450) on Friday.

Delhi air pollution today: How is the air quality in the NCR region?

In most cities around Delhi, the AQI was in the "severe" category. Faridabad's AQI was 460 and 440 in Noida. Sonipat's AQI was 374. Greater Noida's AQI was 494. However, Gurugram's AQI was "very poor" at 367.

What is the Delhi government doing to curb pollution?

Invoking stage III of the pollution control plan, deploying anti-smog guns and re-launching the 'Red light on, Gaadi off' campaign are among the measures taken by the Delhi government and other agencies with the city's air quality entering the 'severe' category, officials said.

According to a Delhi government official, the Graded Response Action Plan (GRAP) stage 3 has been implemented in the national capital with a complete ban on construction or demolition activities.

The Centre's pollution control panel invoked the GRAP III on Thursday, directing a halt on non-essential construction work, stone crushing and mining in Delhi-NCR. Under this stage, restrictions are also imposed on the operation of BS III petrol and BS IV diesel four-wheelers in Delhi, Gurugram, Faridabad, Ghaziabad, and Gautam Budh Nagar.

The Delhi administration, which has stepped up measures to tackle the pollution menace, has deployed anti-smog guns in several places such as Anand Vihar, Kashmiri Gate ISBT, ITO, Pusa Road, Jahangirpuri, Narela Industrial area, and Burari Crossing, officials said.

The Delhi government launched the 'Red light on, Gaadi off' campaign on October 28 to make commuters and motorists aware about the growing pollution and encourage them to switch off their vehicles while waiting for the traffic light to turn green. It was re-launched a year after Lieutenant Governor V K Saxena put it on hold, questioning its effectiveness.

Environment Minister Gopal Rai had earlier said 2,500 civil defence volunteers will be deployed for the campaign to monitor its implementation at 100 key traffic intersections.

Gopal Rai also appealed to the Chief Minister of the bordering state, Uttar Pradesh to stop services of the BS3 petrol and BS4 diesel vehicles to the national capital.

"In Delhi, there are only electric buses and CNG buses but from UP, banned BS3 and BS4 vehicles are being sent to Anand Vihar bus depot. It's my request to the Uttar Pradesh government, to stop sending such vehicles that emit so much smoke...we have stopped all the construction in Delhi currently, and BS3 & BS4 vehicles are banned," Rai said. 

What is AQI?

The air quality index shows the air quality status of people. There are six AQI categories, namely good, satisfactory, moderately polluted, poor, very poor, and severe.

Each of these categories is decided based on the ambient concentration values of air pollutants and their likely health impacts (known as health breakpoints). According to the AQI scale, the air quality check between 0 and 50 is "good", 51 and 100 "satisfactory", 101 and 200 "moderate", 201 and 300 "poor", 301 and 400 "very poor", and 401 and 450 "severe".

What is Grap?

The Centre's Pollution Control Board (PCB) has devised a Graded Response Action Plan (Grap) to contain worsening pollution in the national capital. As the name suggests, it is a graded response measure employed depending on the severity of the air quality. It has four different sets of response stages.

Under Stage I, construction and demolition activities on a plot size of or above 500 square meters are prohibited. Restaurants and hotels are directed to stop using coal and firewood in tandoors. Moreover, the government has begun automated cleaning of the roads for dust management. It is brought into effect when AQI is "poor".

Under Stage II, the parking fees are hiked to penalise the usage of private vehicles. To encourage usage of public transport, the frequency of local buses and Metro is increased. It is initiated when AQI is "very poor".

Under Stage III, BS-III petrol and BS-IV diesel four-wheelers are prohibited from entering Delhi-NCR, in addition to other measures. Moreover, all construction activities, except government projects, are stopped. The entry of commercial vehicles registered outside Delhi is prohibited in the capital. This stage is activated when AQI is "severe". Currently, this stage has been imposed in the national capital.

Under Stage IV, all construction and demolition activity, government or private, is completely banned. Online classes and provisions for remote work are made. The government starts this stage when the pollution levels are "severe-plus".

(With agency inputs)