JOIN USAir pollution levels in the city are lower now than they were a decade ago – before buses were compelled to uses only compressed natural gas (CNG), an environment-friendly Metro appeared on the scene and many industries pushed out out.
But complacency can be dangerous. Rising pollution has merely been arrested, experts warn.
A 2010 survey by the Central Pollution Control Board (CPCB) highlighted that Delhi was still the most polluted city among the major ones in the country. “The situation has not improved till date.
The quality of air is not breathable,” said Sumit Sharma, associate fellow at The Energy and Resource Institute (TERI).
Enviornmentalists say it is a tough task to make pollution control interventions work in a busy city with a growing population. And they agree that air quality control has shown results over the years. But they strongly believe that there is much room for improvement.
“Despite being one of the most polluted cities in the country, Delhi was able to arrest and even lower air pollution levels after the first phase of action in 2002. Delhi has taken action in nearly all sectors to control air pollution over the past decade. But despite the initial air quality gains, Delhi faces the challenge of meeting the clean air goal,” said Anumita Roy Chowdhury from the Centre for Science and Environment (CSE).
Delhi has implemented significant measures such as relocation of industries from the main city to the outskirts, stricter control on power plants, implementation of the natural gas vehicle programme, improvement in vehicle technology and fuel quality, restricting more than eight-year-old heavy vehicles from entering the city limits and improvement in emission regulations.
“Immediately after the implementation of the CNG programme (in 2002), the CPCB had reported about 24 per cent drop in particulate levels from the 1996 levels.
Also, a study by the scientists at Jawaharlal Nehru University had shown significant drop in the levels of polycyclic aromatic hydrocarbons, which are a group of extremely toxic pollutants, in Delhi’s air immediately after the introduction of the CNG programme,” reminded Paritosh Tyagi, former chairperson of CPCB.
Multi-pollutant crisis
But now, studies by several environmental NGOs have begun suggesting that Delhi has not been able to sustain the gains of such interventions as air pollution levels are rising again.
TERI's Sumit Sharma said exposure to high levels of particulate pollution remains a major health concern, but there is also a need to deal with the rising level of other pollutants. “The city is now facing a multi-pollutant crisis. Delhi now needs to worry about rising nitrogen oxide (NOx), ozone and air toxics for the coming generations,” he said.
The CSE points out that particulate matter or PM levels are still “unacceptably high and continue to be substantially above the national ambient air quality standards.” Delhi's PM level is around 60 when it should be 10.
After initial stabilisation, particulate levels have begun to rise again. The CSE's analysis has revealed that the recent data from the CPCB on tinier particles called PM2.5 – which can go deep into the lungs and cause serious health damage – is showing high levels, especially during winter months. During winter, PM2.5 levels have recorded 1.5 times the norm on all monitored days.
Nitrogen dioxide (NO2) levels, a measure of Nox presence, have also increased significantly in Delhi. “This pollutant strongly correlates with motorisation and vehicular movement. We had conducted a study in Bangalore where we discovered that more than 67 per cent of NOx comes from the vehicular sector and 25 per cent from diesel generators,” added Sharma.
Ozone threat
Along with the common pollution threats, formation of an ozone layer at the breathing level in Delhi is emerging as a new threat.
TERI and the CSE pointed out that uncommonly high levels of ozone have been recorded during summer months.
“Other pollutants such as nitrogen oxides and hydrocarbons from the growing number of vehicles and other sources react in the atmosphere under the influence of sunlight and high temperature to form ozone. This is dangerous,” said Sharma.
Short term exposure to high levels of ozone can be harmful, especially to children, asthmatic patients and the elderly.
Air pollution shows varying trends in different city locations.
“While annual average levels are rising steadily in most locations, the annual maximum peaks are also hitting dizzying heights causing very high exposure,” states a recent report by the CSE on air pollution.
However, the Delhi Pollution Control Committee (DPCC) believes that it is difficult to define air pollution levels as the city is vast.
“There are several pollutants where levels keep fluctuating. Also, nobody knows how to average the ambient air quality in the city as activity levels are not same across the city,” said Sandeep Kumar Mishra, member secretary, DPCC.
Mishra added that since pollutants disperse according to the flow of the wind it becomes difficult to define pollution levels. “We have approved a two-year study plan which will be conducted by IIT-Kanpur to get an idea about the persistent issues and ways to solve them,” he said.
Vehicles big culprits
Vehicles are one of the most rapidly growing sources of pollution. According to the Economic Survey of Delhi, the city has about 6.4 million registered vehicles and adds nearly 1,200 a day from neighbouring cities.
It has been highlighted several times that pollution concentration in the breathing sphere is 3 or 4 times higher than the ambient air concentration.
New research in Delhi by the University of California, Berkeley found that commuters breathe far more harmful particles inside cars compared to any other form of transport.
“The PM2.5 concentrations inside vehicles can be 1.5 times higher than the surrounding background air and ultra-fine levels about 8.5 times higher,” states the research.
“The short-term peaks during travel can go above 1000 microgramme per cum – nearly 16 times the daily limit,” adds the research. Experts added that some of the deadliest air toxics and carcinogens are part of vehicular emissions which have been linked to foetus deaths.
Way ahead
Environmentalists demand a source-wise action plan. “The action plan should address the most toxic sources on a priority basis and deliver multi-pollutant benefits. We need to begin educating at the school-level to promote traditional living methods,”said Gaurav Shorey, assistant professor with Sushant School of Architecture.
Delhi has multiple sources of air pollution such as vehicles, industries, diesel generator sets, cooking gas and biomass. Pollution can also rise because of construction activity.
CSE's Anumita Chowdhury called for a stringent action plan for reducing the number of vehicles and the congestion caused by them.
“Also, there are no clear mechanisms to meet with the National Indian Quality Standards. These standards must become legally binding to ensure that the situation can be rectified,” she added.
The DPCC said that they are working with the CSE to finalise a five-year-plan to combat pollution and the agenda will be formed by the end of this month.
The CSE believes this agenda will be a blueprint for the next generation. It will asses the quality of air and identify challenges which need to be addressed with tough strategies.
Polluting emissions should be reduced by introducing stronger norms, add experts.
The CPCB calls for a gradual shift from cars and buses to the Metro, and encouraging cyclists in the city.
“We also need to redesign our products in such a way that they meet with the norms of the four Rs – Reuse, Recycle, Reduce and Recover,” said Mishra.