Battle of clean air

The pollution level in the city of Delhi has reached alarming proportions over the years and winter haze is a regular sight in northern India. In an effort to clear the hazy skies, the government declared a public health emergency, restricting car use, shutting primary schools and halting construction projects. These measures could not solve the acute air quality crisis though it certainly reduced peak pollution loads. However, these actions create awareness among the middle class. People have realised that the severity of the problem is increasing faster than the government's capacity to respond. In many areas over the weekend, levels of the deadly particulate matter reached around 60 times the global safety threshold or the equivalent of smoking more than two packs of cigarettes a day.

The major cause of acute air pollution crisis in Delhi is attributed to its geographical location. Delhi is practically a land-locked megacity with limited avenues for the flushing of polluted air out of the city or its replacement with air from relatively unpolluted marine regions. These critical features are common in many growing non-coastal megacities. The problem of very poor flushing out is further aggravated on account of unplanned urbanisation with massive development of housing and commercial space within the core of these cities without optimising urban function and spatial layout. During winters, cold air moves down the Himalaya Mountains, settling over northern India's Ganges Plain. This layer of cold air gets trapped beneath a layer of warmer air. Since the cold air cannot rise above the warm air, pollution builds in the cold air as long as the temperature inversion lasts. In contrast, those megacities which are located close to coastlines benefit from sea breeze that can exchange maritime and urban air on a diurnal cycle.

About 65 per cent of pollution is clearly attributed to rapid economic growth that has resulted in an increase in motor vehicle, unplanned urbanisation, industrial and agricultural activities. During November, smoke from upwind agricultural burning combines with Delhi's year-round urban pollution — a toxic mix of vehicle exhaust, industrial emissions, garbage burning in open and in landfills and construction dust — caused an eye-watering smog. Fireworks from Diwali celebrations further aggravate the city's air pollution crisis.

One of the most dangerous components of air pollution is fine particulate matter. This fine pollution mainly comes from burning things: Coal in power plants, gasoline in cars, chemicals in industrial processes or woody materials and whatever else ignites during wildfires. The particles are too small for the eye to see — each about 35 times smaller than a grain of fine beach sand — but in high concentrations, they cast a haze in the sky. These particles can penetrate deeply into the lungs causing serious health complications. People are exposed to harmful particulate matter from industries, too but fires produce fine particles into the air at a rate three times as high as levels noted in emissions inventories at the U.S. Environmental Protection Agency, according to a new study. According to estimates by the WHO (World Health Organisation), ambient outdoor air pollution causes 1.3 million urban deaths worldwide each year. Exposure to these particles is estimated to cause 12.4 lakh deaths aged less than 70 in 2017 and 77 per cent of India's population is exposed to outdoor air pollution across India.

The impact of particulate matter on human health has been highlighted elaborately but the effects of the fine particulates on plant matter remains neglected. Tiny pores in the leaves, the stomata are the gatekeepers that regulate how much water vapour is released to the atmosphere. Stomata also allow carbon dioxide for photosynthetic production of energy-storing sugars. This causes a dilemma for plants, between thirst and starvation. Closing the stomata saves water but restricts the uptake of carbon dioxide or opening the pores allow carbon dioxide to enter but at the cost of increased water loss. Plants have adapted stomatal regulation to prevailing ambient conditions over evolutionary timescales but particulate matter concentrations with toxic compounds were generally much lower than they are today as advocated by the researchers.

In recent past, severity of air pollution problem in metropolis and cities is highlighted but the people living in rural areas are also badly suffering due to trans-boundary movement of the pollutants originating from thermal power plant, sponge iron, coal washeries, crop burning, households and others. But this problem remains well hidden. The insufficient understanding of public pro-environmental intentions and behaviours has become a barrier to implementing appropriate regulations for air quality improvement.

The regulatory agencies have stipulated a series of actions for almost all sectors to control air pollution over the past decade. These actions include relocation of polluting industries, introduction of improved emission norms for vehicles, phasing out of lead from gasoline, reduction of sulphur in diesel and benzene in gasoline, running the city public transport fleet on compressed natural gas (CNG) and banning of 15-year old commercial vehicles in many areas. The government has also implemented BSIV standards for vehicular technology and fuel in Delhi and other metropolitan cities of India in 2010. Despite these initiatives, data generated over the years reveal that air pollution levels are still far above the permissible levels at many sites across India.

Most importantly, the pollutants such as particularly polyaromatic hydrocarbon (PAH), mercury, volatile organic carbon and benzene that are carcinogenic in their effect were found in relatively higher amounts than the values reported by regulatory authorities in many cities. Any decline in pollutant levels observed in a particular year is mainly due to the influence of meteorological factors particularly wind speed and rainfall.

Regulatory authorities frame the rules/regulations/ permissible levels and serve notices to noncompliant organisations but without any sincere thought given to their implementation. Our political rulers or governments both in centre and states ignore the gulf between permissible standards stipulated by the regulatory authorities and controlling air pollution realities at their sources.

Regulatory pressure compelled these industries to adopt the end-of-pipe treatment technique to mitigate environmental pollution. The regulatory agencies inspect the industries once or twice in a year but are unable to ensure consistent control of pollution. It is not always feasible with limited experience personnel to continuously monitor environmental performance over time. Reducing this pollution problem needs environmental improvement at the micro-level, a goal which has been stubbornly elusive in India. In this context, it is pertinent to mention that Sustainable Development (SD) that is defined as "development that meets the needs of the present without compromising the ability of future generations to meet their own needs" cannot be maintained to balance industrial growth and environment. To fulfil this requirement, it is necessary to create changes in industrial production, transportation system, agriculture activities, domestic consumption and solid waste management through adoption of Cleaner production (CP) principles and practices that could support economic and environmental benefits. Cost-effective CP can improve material utilization and reduce energy consumption and waste emission. The proper understanding of these benefits among the owners' of these sectors could help them to invest in infrastructure, including clean technologies and environmental capacity, fostering CP implementation.

Most importantly, the CP concept must be pursued to reduce pollution intensity of iron and steel, cement, chemical, petrochemical and other key industries with the increase of green coverage, water area, ecological and clean-type watersheds in these industrial premises. Also, city plans must be done based on an airshed approach with a clear understanding of the topography and meteorology that impact level of pollutant concentrations, not simply cut-and-paste report by consultants based on spurious primary and secondary data.

The monetary quantification of the damages associated with pollution is a very controversial issue due to technical, political and ethical issues. Furthermore, the determination of environmental damages in monetary terms is very difficult to achieve due to the difficulty in measuring the damage generated by each source according to its spatial location, the difficulties to monitor and enforce the environmental policies, the uncertainty associated with the estimation of costs and benefits, the existence of previous distortions in the markets and also, the political, distributive and financial costs required to implement environmental regulations.

Sound environmental policy guided by science can control air pollution and save lives, money and ecosystems but at present, science faces scepticism because of the paucity of facts and data that matter. The harmful emissions from various sources to be curtailed must be validated by monitoring and evaluation, pollution source apportionment and emission inventories, which are the most important requisites in evaluating the success or failure of environmental policies. It also contains comprehensive legal standards and strict environmental law enforcement. Air quality work must be supported by economic policies and coordination on air pollution prevention and control in the air pollution crisis region.

Reliable ambient air quality data is urgently needed to recalibrate strategies if they are not working. At present, hourly assessments of concentrations of nitrogen dioxide, sulphur dioxide, ozone and particles measuring less than 2.5 µ (PM2.5) and less than 10 µ (PM 10) are being carried out by automatic analysers installed at huge expense which will not serve any actual purpose because hourly data is not properly used to calculate monthly averages and determine overall concentration levels correlating meteorological influence that is most critical factor in clear statistical terms on regular basis. Thereby, pollutant concentrations that have changed i.e., the actual trend over the years with reference to the meteorological condition cannot be brought to the public domain. Moreover, adequacy and reliability of these real-time analysis data is questionable if we compare this data with manual data.

Air pollution problems must be addressed through collective and enforceable actions based on sound scientific evidence of serious air quality issues across India. These should include improved urban and transportation planning, improved fuel standards and emission control (especially targeting vehicles, power generation and industries that contribute significantly to air pollution).

In addition to the government's efforts to develop a legal system using technological tools or top-down approaches, public participation is also essential to achieve sustainable development. A shift towards renewable energy must be included in the plan to reduce dependency on fossil fuels as well as provide clean energy to households to tackle air pollution problem and climate change.

The improvement in air quality cannot happen in a day. It needs an enormous investment of time, resources, sound scientific evidence and overall political will, not political blame games.

Most importantly, before taking any action to tackle the pollution crisis, competent authorities need to better understand the causes of pollution.

Dr Debapriya Mukherjee is a former Senior Scientist, Central Pollution Control Board. Views expressed are strictly personal