Diwali was cleaner but there’s no reason to celebrate, say experts

Air quality in the range of 301-400 can cause "respiratory illness on prolonged exposure". (Image: AP)

Favourable weather conditions spared Delhi-NCR of the worst of the post-Diwali smog this year but there’s no reason to cheer, warn environmental experts. The pollution menace is very much alive and kicking, and only long-term measures and proper execution of rules can help alleviate the annual air-quality emergency, experts say.

The reasons behind Delhi-NCR’s pollution — now a pan-north India issue that leaves people gasping for fresh air every winter — are now known to all.

The triggers include post-harvest stubble burning by farmers; vehicular pollution; biomass, solid fuel and waste burning; industrial emissions; dust from construction sites and degraded land; firecracker bursting during Diwali, etc.

Also Read: Stubble burning contribution to Delhi's pollution increases to 10% on Diwali

While most factors exist even in summers, adverse weather conditions in winters, such as falling temperatures, moisture in the air that traps ultra-fine and hazardous particles, as well as the calm wind, aggravate the problem.

“Delhi has its own higher emission load because of high vehicle population, traffic congestion, road and construction dust, and industries in the periphery,” said VK Soni, head of the Environment Monitoring & Research Centre, India Meteorological Department (IMD).

“Combined with stubble fires, this additional load leads to extreme pollution events not only in Delhi but the entire Indo-Gangetic plain,” he said.

The story so far

This year, favourable meteorological conditions have ensured the region was spared of a severe pollution episode thus far.

Last month, the air quality index (AQI) stayed mostly in the satisfactory and moderate range owing to a rain spell from September 14 to 25. On October 5, the AQI entered the poor category for the first time since June 25.

But yet another rain spell from October 7 helped the air stay in the moderate zone till October 16, when the AQI once again entered the poor category.

The air quality continued in the poor zone till October 24, Diwali, when it entered the very poor category for the first time this season, recording an AQI of 312.

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’.

Also Read: Delhi's post-Diwali air quality best in five years: Gopal Rai

A cleaner Diwali

The day after Diwali did not turn out to be as bad as feared, mainly on account of the relatively warm weather as the festival was celebrated earlier than usual and thanks to a constant wind speed that prevented the remnants from settling down.

Last year, Diwali was celebrated on November 4 and on November 14 in 2020, when the temperatures were lower, and the winds calm.

On November 24, Diwali day, Delhi’s AQI was recorded at 312. On November 25 morning, the AQI was 325 at 6 am and 302 at 4 pm, the lowest for the day after Diwali since 2015, Central Pollution Control Board data showed.

Last year, an AQI of 382 (very poor) was recorded on Diwali, which shot up to 462 (severe) a day later. The year before, the AQI on Diwali was 414, which rose to 435 a day later. An AQI of 360 was recorded a day after Diwali in 2015, 445 in 2016, 403 in 2017, 390 in 2018 and 368 in 2019.

Delhi’s neighbours more or less followed a similar pattern. This year, on November 25, Ghaziabad’s AQI was 266, Noida 299, Greater Noida 272, Gurugram 292 and Faridabad 289 — all in the poor category.

Fewer farm fires

The rains also postponed the harvest season, which delayed stubble burning by farmers. So, on Diwali day, farm fires were lower than usual.

Farm fires rise sharply in winters — mostly from mid-September till November end, after the harvesting of the kharif crop — when farmers clear the fields for the rabi crop.

This year, there were 1,484 farm fires in Punjab, Haryana, and Uttar Pradesh on October 24. Punjab reported 1,019 cases, Haryana: 250 and UP: 215, according Indian Agricultural Research Institute (IARI) data. Smoke from these states affects Delhi-NCR the most.

In comparison, in 2021, there were 3,383 farm fires across Punjab (3,032), Haryana (228), and UP (123) on Diwali day on November 4.

This season’s total in the three states from September 15 to October 25 was 7,731 cases — 5,798 in Punjab, 1,372 in Haryana, and 561 in UP. In 2021, during the same period, 8,564 cases were reported from Punjab (6,058), Haryana (1,835) and UP (671).

But from September 15 to November 4, 2021, when Diwali was celebrated, the total number of farm fires in the three states rose to 28,769 — a huge spike. Punjab recorded 23,610 cases in this period, Haryana 3,666 and UP 1,493 cases, the IARI data showed.

But experts say the decline this year is little reason to celebrate as the tide could turn any moment.

“The weather was warm and a wind speed of about 9 km per hour ensured the pollutants didn’t stagnate. The farm fire count was low. The scene would have been entirely different had Diwali been celebrated after 15 days,” Gufran Beig, founder project director of SAFAR (System of Air Quality and Weather Forecasting and Research), told Moneycontrol. The wind direction is working in our favour at the moment but it may reverse, he warned.

Chandra Bhushan, CEO of the International Forum for Environment, Sustainability and Technology, said nature should be credited more than anything else. “Remember that the AQI may have been lower but it is still more than 250 at most places, which is not good news.”

Forecast-based action plan

This year, the Commission for Air Quality Management (CAQM) in the National Capital Region and Adjoining Areas, which oversees and implements decisions related to pollution, introduced a revised graded response action plan (GRAP).

The GRAP comprises anti-air-pollution measures executed depending on how the air quality deteriorates. The restrictions get stricter as AQI worsens.

The steps include a ban on diesel generators, an odd-even road rationing policy, a ban on construction, closure of brick kilns, stone crushers and hot mix plants, sprinkling of water, etc., depending on the category of the air pollution.

Stage 1 of the restrictions is imposed when the AQI turns poor, stage 2 when it is very poor, stage 3 when it is severe and stage 4 when it is severe plus.

The restrictions were earlier imposed only when the PM2.5 and PM10 levels reached a certain threshold. But now, they are based on forecasts released by the early warning system (EWS) and a more comprehensive AQI.

The EWS was developed by the Indian Institute of Tropical Meteorology – Pune, IMD and the National Centre for Medium Range Weather Forecasting.

The department issues an air quality forecast for three days and a further outlook for seven days so that pollution control authorities can initiate action in advance, Soni said. CAQM and other agencies initiated early action this season to curb the emissions, he said.

“The AQI was expected to reach the very poor category before Diwali but it did not deteriorate to that level. This proved the control measures are very effective,” Soni said.
Stronger execution

Anumita Roychowdhury, executive director, research and advocacy, Centre for Science and Environment, while welcoming the forecast-based GRAP, noted that the severity of the smog episodes would be determined by the effectiveness and scale of implementation of measures across Delhi-NCR.

“It will also depend on the strength of the long-term action taken to build infrastructure and systems in all the sectors, including transport, industry, power plants, waste management, construction and household fuels,” she said.

Bhushan wondered if all the GRAP actions combined would be enough to combat and reduce pollution, which has reached alarming levels in the region.

Stressing on proper enforcement, he said there is a need to drastically cut down on biomass burning, which spikes during winters as many people use wood and other solid fuels to keep warm.

Better alternatives such as LPG and clean fuel to the poor would help, Bhushan said, adding that a massive boost to public transport could go a long way to reduce personal vehicle use and cut automobile pollution.

“Look at China. They removed coal-based industries, took strict action on industrial pollution, reduced solid fuel burning, boosted public transport and invested in green cover,” he said.Economic issue, long-term plan

Air pollution is a complex issue and addressing it cannot be reduced to just discussing bad air in the “air pollution” season, cautioned Prarthana Borah, director of CDP India, a not-for-profit that recommends how organisations can lessen their environmental impact.

Borah said multiple measures have been suggested and implemented but we need to introspect if these have been effective or not.

Difficult questions need to be asked in terms of policy implementation, she said, adding there is a need to question if the mechanism tracking implementation of measures vis-à-vis the impact on air pollution is adequate.

“Is there a target year for a pollution-free Delhi and if so what is the science-based mechanism we are adopting to achieve it? Which sectors are involved and what targets and implementation strategies are being adopted?”

Air needs to be translated from just an environmental and health issue to an economic issue and the private sector, especially the industry, needs to be involved if this has to be the case.

“This is a complex area but needs to be done,” Borah said. For example, the number of work days lost due to air pollution-related health issues can be factored in so that companies take the initiative to address it.

People's engagement is crucial to addressing air pollution, most experts said.

“Despite the ban, cracker burning could not be stopped. I saw a father teaching a child to burn a cracker because it is the ‘essence of Diwali’. Unless this narrative changes to telling each and every one that cracker burning is hazardous, no amount of policy or mitigation measures can help,” Borah said.

This goes for other topics such as using public transport over using a car and reusing and recycling instead of burning or dumping.

Other experts focused on a long-term, regional and a multi-sectoral plan to meet the challenge as multiple states and agencies are involved.

According to Beig, to clean Delhi, the impact of the measures should be long-term and felt at least 150 km from the capital. “During the nationwide lockdown, the air got cleaner across India. But when Delhi remained locked down and nearby areas opened up, it didn’t help as air knows no boundaries.”

Roychowdhury said the fully opened economy and unrestricted travel post-pandemic will add to the challenge. “The concern over winter pollution has to catalyse deeper and uniform systemic changes across the entire region. This means all state governments need to implement an aligned multi-sector action,” she said.