Air pollution in Delhi worsens during Diwali. But air pollution cannot be brushed off as something that affects people only during Diwali. Poor air quality is now commonplace across India's cities. Concentrations of fine particles have been on the rise. In Delhi, particulate matter concentrations average 125 micrograms per cubic meter annually, despite a countrywide regulation stating that annual average concentrations should not exceed 40 µg/m3. The concentration baseline has shifted as the rises in population, urbanization and motorization have occurred without the application of emissions reduction mechanisms that are practised across the rest of the world.
Air pollution concentrations are measured using surface-based monitors. These monitors are also used to publicly report on and regulate air pollution. In India, the Central Pollution Control Board's data are being compiled into online databases to create air quality forecasts, which are easily accessible and frequently updated. These databases are necessary because currently the CPCB's own online data portal is not entirely user-friendly. Online reports are not prepared and disseminated daily. Current reports on air quality conditions are important for people to take decisions about their lives related to spending time outdoors. Moreover, most monitors are located in urban areas. Obtaining information on pollution outside major cities is thus challenging.
How do other countries fare in dealing with air pollution? China is making great strides to reduce urban pollution. Stringent regulations have been imposed on industries to improve air quality. European and North American cities have long fought to improve air quality by regulating ambient concentrations and emissions from mobile and stationary sources. Although investing in efforts to reduce pollution can be expensive - in the US air quality regulatory expenses exceed 50 billion dollars annually - this has not prevented economic development.
In India, premature deaths attributed to particulate matter pollution range between 486,000 and 570,000 per year as found by two studies published in early 2016. Improving air quality can be achieved through mitigation efforts. There are numerous practical solutions to improve air quality across India, but they will require rigorous data collection methods, continuous monitoring and strictly enforced regulations. Delhi instituted odd-even traffic restrictions to alleviate pollution. The initiative, which decreased pollution levels marginally, will work better in conjunction with other interventions.
Addressing the problem should begin with the collection of data. Air pollution should also be understood at different scales. For instance, what are the different emission sectors, and how do anthropogenic combustion and land-uses, such as crop-burning in Punjab, contribute to Delhi's ambient air pollution problem? So far, we know about urban pollution because that's where most monitors are located. But there is a paucity of data on rural areas. We know about emissions related to transportation vehicles and fuels, but knowledge is limited of the types and quantities of fuel burned for industrial activities or in power plants. Evidence shows that most urban ambient pollution comes from anthropogenic sources related to industry, electricity generation, transportation and residential heating and cooking. Emissions from these sources are often compounded by meteorological impacts, which are misconstrued as the root causes of pollution.
Reducing emissions is expensive. Mitigation strategies need to be targeted and data-driven. Improving air quality can bring significant changes to India by increasing life spans and savings. Diwali should not be the only time that reminds us about the air pollution problems faced by Indian cities.
