Winter pollution is back with a difference. City now faces the threat of multiple pollutants going up together

  • Not only are the tiny particles choking us, nitrogen dioxide levels have worsened; daily peaks of carbon monoxide are unacceptable, ozone pollution has persisted through the winter months. This has emerged from the official public information system on daily air pollution and monitoring. Some of these pollutants come predominantly from vehicles.

  • This cocktail of toxic gases and particles is alarming in a city already experiencing severe respiratory health problems. These underlying diseases make people more vulnerable to the toxic air. 

  • Second generation reforms will have to scale up public transport, cycling and walking, reduce traffic volume and get the cleanest vehicles quickly. Daily smog alert should target to reduce daily dose of toxins.

New Delhi, December 13, 2010: The Centre for Science and Environment has reviewed the magnitude of the winter air pollution in Delhi and has pressed the alarm button. This time the winter pollution is not only high but is also different. While the serious concern over very high levels of tiny particles persists, more pollutants have also scaled the dizzy heights to add to the toxic cocktail. Improvement in official air pollution reporting helps to assess the risk better.

High levels of several pollutants has magnified health concerns manifold in the city. The official disease statistics shows that the reported cases of acute respiratory diseases have already increased by about 28 per cent between 2005 and 2008 in Delhi.  These along with other respiratory and cardiac conditions amongst the city population enhance the impact of air pollution and also increase the vulnerability and health risks to the people.

“Unfortunately, despite the scary hard facts about the elevated cocktail of pollution and health risks, official effort to drive public policy more aggressively to reduce the daily dose of pollution and exposure, is still weak,” says Anumita Roychowdhury, Associate Director, Centre for Science and Environment.

What has the latest CSE review of winter pollution exposed?

  • Delhi localities are in grip of multi-pollutant crisis: The official air quality index (of CPCB and Aria Technologies) shows several locations in Delhi are reeling under cocktail of pollutants. For instance, the review of the first 10 days of December shows that both PM2.5 and NO2 have reached “unhealthy levels”. Even carbon monoxide show unhealthy levels in ITO, Connaught Place, around Central Pollution Control Board office, Karol Bagh, Velodrome stadium, Indira Gandhi stadium. Small particles aggravate respiratory and cardiac symptoms in the short term and trigger lung cancer in the long term, NO2 is a trigger of serious respiratory condition and sudden death syndrome among infants. Carbon-monoxide curdles blood.

  • Cold weather has led to rapid build up of winter pollution: The rapid build up of pollution since the rainy month of August is stunning. For instance, the PM2.5 levels exceeded the standards on 12 days in August. But in November and the first week of December all days have violated the standards and the levels have also hit “critical level” which is more than 1.5 times the standards.  Similarly, not a single day had violated the nitrogen dioxide standard during August. But it exceeded the standards on 13 days in November and all the days in December so far. In December the levels have remained consistently in “high range” and on couple of days even hit the “critical range.”

  • Pollution strongly correlates with the peak traffic hours: Further monitoring by the Delhi Pollution Control Committee in different localities of Delhi shows that pollution levels peak significantly during peak traffic hours compared to off peak hours. For instance:

  • In R K Puram, a residential area in South Delhi, nitrogen oxides concentration during evening peak hours, as noted this month, are more than double the off peak hours.  PM 2.5 concentrations in morning peak hours are also more than double the off peak hours.

  • In Civil Lines, a residential area in North Delhi, nitrogen oxides concentrations are more than double during peak hours compared to the off peak hours in December.

  • At Indira Gandhi International Airport that draws heavy car traffic nitrogen dioxides concentrations drastically shoots up during evening peak hours in December. In November, the eight hour average of carbon-monoxide concentrations exceeded the standard of 2 micrograms/cu m. by more than 3.5 times

  • Ozone pollution persist through the winter months:  It is scary that the ozone levels have continued to exceed standards during the colder months. For instance, the air quality monitoring by the Delhi Pollution Control Committee in Civil Lines shows that out of the 30 days in November, Ozone concentration (8 hourly average) has exceeded the standard of 100 microgram/cu m. on 28 days. The hourly levels of ozone have exceeded the hourly standard of 180 micrograms/cum. and that normally happens between 9 AM and 3 PM during the day when the sun is brightest. Ozone is not directly emitted by any source but is created from reaction between NOx and the volatile organic compounds in the air under the influence of sunlight. The peak levels have hit such high levels of 268mcirograms/cum.

  • Cocktail of pollution can be deadly in Delhi already gasping for breath:  Such high level of particulate matter and several other pollutants is a bad news in a city where according to the National Health Profile of the Central Bureau of Health Intelligence, the number of reported acute respiratory infection cases has increased by 28% between 2005 and 2008. High prevalence of respiratory problems makes people, especially the sensitive population more vulnerable to air pollution.

Other governments act on daily pollution alerts: 
During high pollution episodes Paris authorities recommend drivers to postpone trips to Paris; or bypass Paris city; use public transport; organize car-pooling; minimize combustion of high sulphur fuels in industry; curtail industrial operations and so on.  In Mexico phase one pollution alert requires cutting down of 30-40% of industrial pollution; halting of 50% of government of vehicles; stopping of most polluting vehicles; alternative fuel vehicles are exempted from restrictions; In phase 2 alert schools are closed; One day a week ban on vehicles are extended to two days etc. phase 3 alert leads to closing down of industry in addition to the other curtailment. Berlin does not allow older polluting vehicles in the city centre in any case. Other governments take daily pollution levels very seriously to protect public health. 

Delhi has exhausted soft options
The city has already advanced emission norms; strengthened its ‘pollution under control’ programme; implemented CNG programme; and restricted a great part of commercial vehicles from entering the city. The next steps need to combat not only the rising pollution but also the high mixture of pollutants. This is challenging in a city that already has 5.6 million registered vehicles and adds more than 1100 new personal vehicles a day. This is almost double what was added in the city in pre-CNG days. The market share of diesel cars already at over 35 per cent is expected to be 50 per cent of car sales soon. Even the so-called ‘clean’ diesel running on fuel with 50 ppm of sulphur, allows higher limits for NOx and particulate emissions compared to petrol cars. It is also taking time to scale up public transport systems, their integration and connectivity between the growing cities of the National Capital Region. Traffic volume has exceeded designed capacity on all arterial roads making more than half of Delhiites living within the influence zone of these roads more vulnerable to traffic emissions.

Need action
At this rate, every winter will turn back the pollution clock. Every year, asthma and other respiratory diseases will only increase. A composite health assessment of air pollution is needed in the city. If Delhi does not want to wheeze, choke and sneeze, it must act immediately and aggressively to reduce daily pollution levels:

  • Complete and scale up key public transport projects. Reform bus transport and management urgently for maximum connectivity, comfort and to keep it affordable for the majority.

  • Augment walking and cycling facilities for green commuting and public transport integration. Pedestrianise key and busy commercial areas that are well connected.

  • Reduce traffic on key arterial roads with the help of traffic restraint measures, and voluntary measures (For example, car pooling, staggered office timing, park and ride, parking controls etc.)

  • Accelerate emissions standards roadmap for clean vehicles and fuels to cut emissions are source

  • Use smog alert system for effective measures. Designate and authorize agencies to carry out such plans.

  • Physically remove visibly smoking vehicles. Enforce emissions checks on in-use vehicles.

  • Regulate and reduce the daily influx of traffic from outside. Augment intercity public transport connectivity and ridership.

  • Draw up action plan for other pollution sources as well.

Only the compulsion to meet the clean air targets can deepen public understanding of what it takes to protect public health. Only this can build public support for aggressive action for sustainability of the city.

For more details, please contact Anumita Roychowdhury at or , Vivek Chattopadhyay at