Looming air pollution crisis beckons urgent attention

AS winter approaches, air pollution is expected to worsen in north-western India, likely arriving earlier and with a stronger impact. This is made worse by bad weather, like low rainfall and weak winds.

This situation is similar to the pandemic period when pollution decreased across most of India due to less economic activity, but pollution levels still rose in the north and central-west regions. Investigations spearheaded by the Aryabhatta Research Institute of Observational Sciences highlighted increased ozone, nitrogen dioxide and carbon monoxide levels in these areas. Notably, when trapped near the earth's surface, these pollutants can exacerbate respiratory conditions.

The looming issue of air pollution in north-west India can be traced significantly to farm practices, with the burning of crop residue at the forefront. Punjab and Haryana, crucial contributors to India's agricultural output, commonly burn the leftover stubble after paddy harvests. Although it is efficient for farmers to quickly clear their fields for the next crop, this method has severe repercussions on the regional air quality.

Crop residue burning releases harmful pollutants into the atmosphere, including particulate matter (PM2.5 and PM10), carbon monoxide, volatile organic compounds and traces of heavy metals. These pollutants contribute to smog formation, degrading visibility and posing serious health risks to millions of residents in the Indo-Gangetic Plains. The particles can penetrate the lungs, exacerbating respiratory diseases and other conditions.

The plains are characterised by their flatness and high population density, which facilitate the trapping of air pollutants. The meteorological conditions prevalent in the winter, such as low wind speeds, temperature inversions and reduced vertical mixing, intensify the problem. Temperature inversion is when a layer of cooler air is trapped near the surface by a layer of warmer air above, effectively acting as a lid that prevents pollutants from dispersing vertically.

As wind speeds drop during the colder months, the dispersal of pollutants is further curtailed, allowing them to accumulate in the lower atmosphere. This phenomenon is particularly noticeable in Delhi, which sits close to the source regions and is often blanketed in thick smog during the winter. The city, already grappling with vehicular emissions, industrial pollutants and construction dust, sees a dramatic increase in pollution levels due to these external agricultural activities.

The economic constraints that farmers face play a role in perpetuating this practice. Alternatives to burning, such as mechanical stubble removal and conversion into bioenergy, are either too costly or insufficiently incentivised, leaving many farmers with little choice but to continue with burning. Government initiatives and technological interventions to provide affordable and sustainable alternatives are crucial to mitigating this issue.

The interplay between agricultural practices and geographical and meteorological factors creates a challenging environment for controlling air pollution. Addressing this requires concerted efforts involving policy reforms, technological advancements and community awareness to transition towards more sustainable farm practices while considering the socio-economic realities of the farmers.

Sophisticated satellite technology has transformed our ability to more precisely understand and analyse air pollution patterns. Researchers can now monitor air pollution with enhanced accuracy and granularity by leveraging data from the NASA and EUMETSAT satellites, complemented by ground-based measurements from instruments like the Compact and Useful PM2.5 Instruments with Gas Sensors (CUPI-Gs). These tools provide a comprehensive overview of the pollution metrics, capturing real-time fluctuations and pinpointing hotspots.

In recent studies, extensive data collection efforts have focused on the NCR, where pollution levels have been notably severe. The analyses reveal that a significant portion of the air quality issues in this area originates from agricultural residue burning in the neighbouring states. By integrating satellite observations with local sensor data, scientists have been able to map out pollution sources and trace their contributions to the regional air quality.

These advances underscore the critical necessity for monitoring and robust data collection to understand the dynamics of pollution dispersion. Such insights are essential for developing targeted interventions and policy measures. Continued investment in both satellite and ground-based observation technology is crucial for devising effective strategies to mitigate air pollution and protect public health in vulnerable regions.

Delhi and its vicinity endure severe particulate matter (PM2.5) pollution levels, recording significantly higher metrics than other regions. Data from 2023 highlights that the NCR saw PM2.5 levels frequently surpassing the safe limits, with some measurements peaking at 218.4 µg/m³. This emphasises the influence of crop stubble burning and stagnant weather conditions in escalating the pollution levels.

Meanwhile, regions like Bihar and Rajasthan have emerged as unexpected pollution hubs, indicating that smaller cities can rival metropolitan pollution challenges.

The findings and patterns emerging from latest air quality studies necessitate a holistic approach to combating air pollution. Various national and international projects, such as the National Clean Air Programme and the RIHN project, AAKASH, have made strides in mitigating pollution.

However, an urgent call remains for immediate, coordinated efforts towards sustainable solutions. Recommendations include stricter enforcement of stubble burning regulations, enhancement of green energy alternatives and increase in public awareness about the health implications of pollution.

Establishing a regional air pollution coordination body is vital for addressing air quality challenges. This entity would serve as a centralised authority to synchronise efforts across states, ensuring comprehensive policy implementation and resource-sharing. It should have representatives from government agencies, NGOs, scientists and community leaders. Its functions would include integrating data from various monitoring networks, facilitating cross-border dialogue on pollution sources and developing unified action plans. The body would also oversee public awareness campaigns and provide funds for innovative pollution reduction technologies. By fostering collaboration and accountability, it would be pivotal in improving the regional air quality.

As we venture into the winter of 2024, the looming air pollution crisis in north-west India beckons urgent attention. The complexities of this issue call for multifaceted solutions. The health of millions hinges on it.