The deadly heatwave that large parts of India, including New Delhi, experienced this summer, was an indication of how climate change is making Indian cities increasingly unliveable. But what went largely unnoticed was that all but one of the heatwave days in May in the capital were days that also had poor air quality. This means that the unusually hot days with temperatures over 45 degrees Celsius were teamed with an air quality index exceeding 200 (‘very unhealthy’ as per the national guidelines).

While one could argue that these environmental threats are not uncommon for an emerging South Asian economy like ours, what is alarming is the scale of the exposure to both these environmental threats. Millions of Indians are being exposed to extreme levels of both air pollution and heat concurrently. Of the 131 cities in India that have exceeded safe air quality limits consistently for the last 10 years, 110 of them lie in heat-prone states. This double whammy of extreme heat and polluted air poses enormous developmental, health and welfare challenges that risk worsening existing structural and societal inequities unless urgently addressed. We need a holistic policy framework that recognises the interconnected nature of these issues and implements measures to address them.

Combined impacts of air pollution and heatwaves

In India, we tend to think about air pollution as a winter phenomenon, worsened by weather patterns and seasonal sources such as stubble burning in north India. However, the high level of polluting emissions in the country from vehicles, power plants and industries round the year mean exposures to air pollution are well beyond safe levels even in the summer. With changes in temperature, the types of pollutants in the air change as well. In addition to PM_2.5 or fine particulate matter which has wide ranging and severe health impacts, the summer brings large concentrations of gaseous pollutants. For example, at high temperatures, harmful pollutants like nitrogen dioxide react with gases in the air to create ozone, which can affect cardiovascular, respiratory and immune systems. Ground-level ozone formation has increased in recent years due to the growth in combustion vehicles of all forms and alarmingly high temperatures in our large urban centres.

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There are four key reasons why we need to pay attention to the combined damaging impacts of air pollution and heatwaves. First, the two threats can create a vicious cycle of poor environmental quality by reinforcing each other – atmospheric ozone traps heat closer to the ground and stagnant air conditions created during heatwaves trap pollutants such as ozone close to the ground.

Second, the health of people exposed to both air pollution and heatwaves simultaneously can be affected quite severely. There is substantial evidence that air and heat both affect respiratory and cardiovascular health, but when combined, can increase mortality even further. A study in Delhi found that deaths due to air pollution are actually higher in the summer relative to the winter, despite higher air pollution levels in winter. Therefore, adopting protective health measures against both air pollution and heatwaves is crucial.

Third, the people most vulnerable to heat and air pollution are the same — those with the lowest ability to adapt. These are people for whom exposure is unavoidable and financial resources to cope are scant. Think of workers in polluted and overheated brick kilns, outdoor daily wage workers, and poor households trapped in sweltering homes with high indoor pollution. They form the majority of India’s population and are frequently excluded from social safety nets, grappling to protect themselves with their dwindling incomes.

Fourth, with a large segment of the working class reeling under the dual impact of these environmental threats, the Indian economy is also vulnerable to extreme heat and polluted air. In damaging the health of many thousands of people, the combined heat-air hazard increases their healthcare expenditure and decreases their ability to work. At a nation-wide scale, these factors will start to affect the economy in the long-run as temperatures and pollution levels continue to rise. The economic impact of air pollution and heat is felt quite severely through the agricultural sector, independently reducing crop yields, and synergistically through rising levels of ground-level ozone.

Read more: Heat wave hits earnings, health of auto rickshaw drivers

Addressing threats in a unified manner

Put together, the scale of the issue is enormous, and dealing with it requires thoughtful, creative, and coordinated actions. To deal with this twin problem, India must adopt a multifaceted policy approach.

First, there must be an acknowledgement of the interconnected nature of these challenges. Next, existing policies on heat and air pollution should be harmonised to deliver deeper impacts. Finally, investments in long-term actions that reduce future impacts and help vulnerable communities adapt to current realities must be made to counter projected temperature rises.

Air pollution and heat are not new issues; existing policies to address them, such as the National Clean Air Programme (NCAP) and Heat Action Plans (HAPs), are already in place. However, they tend to operate in isolation.

The recognition of the intertwined impacts of heat and air pollution remains limited. Delhi’s Air Quality Management Plan and Graded Response Action Plan (GRAP), both fall short in tackling seasonal impacts beyond winter, meaning when temperatures peak in the summer, bureaucrats’ as well as the public’s attention is diverted from air pollution. Some HAPs, like the recently released Delhi Heat Action Plan, have started acknowledging the dual issue and proposing measures to reduce both heat and pollution.

Such siloed operation of these policy instruments can often lead to contradictory advice. For example, HAPs recommend avoiding outdoor activities during peak afternoon heat, while air pollution guidelines suggest avoiding them during mornings and late evenings — typically cooler times — when pollution is at its worst.

These contradictions often result in inaction, which on a hot, polluted day can quickly become dangerous. To avoid this, policies must be based on a recognition of the intertwined impacts of both air pollution and heat. However, recognition alone does not always translate to action. A concerted and immediate effort is required to evaluate and improve the implementation of both plans so they can work in tandem, preparing for a future where inaction is unaffordable.

In the short run, India must explore adaptation measures that safeguard the public against both threats. Effective measures should provide the public with information on the level of exposure to heat and air pollution and their associated health impacts. For example, displaying temperature alongside AQI on LED screens could raise public awareness. This could be complemented by long-term education efforts to inform populations about the combined health impacts of heat and air pollution.

Efforts must also be made to avoid the risk of adaptation measures hindering long-term progress. With summer temperatures frequently crossing 40 degrees Celsius, air conditioning becomes an essential adaptation retreat for many. However, the rising demand for electricity, especially due to the widespread use of energy-inefficient ACs, significantly contributes to peak electricity demand. Much of this demand is met by polluting sources like coal, which not only increases pollution but also exacerbates future temperature rises.

Such maladaptive measures can propel us into a future where the limits of adaptation are long surpassed. While investing in energy-efficient cooling systems is a necessary first step, broader, systemic changes are essential. We must protect the vulnerable from current threats while simultaneously reducing our chances of entering an unliveable, sweltering future. This requires immediate investment in long-term mitigation measures.

Fortunately, some long-term mitigation measures can offer co-benefits for both air quality and temperatures. Advancements in urban greening, renewable energy can help mitigate the impacts of both hazards. These solutions are not quick fixes and must be integrated into our long-term vision for building less polluted, less heat-trapping, and more liveable cities. This can be done by pedestrianising cities, by reducing space otherwise used by cars and increasing local green cover which can reduce heat and air pollution both. Singapore’s Green Plan focuses on planting over a million trees to provide access to cooler shade and cleaner air. Similarly, Barcelona city in Spain constructed superblocks that reduced exposure to polluted air and mitigated the urban heat island effect.

One way to achieve long-term goals is by aligning existing developmental and infrastructure programmes to address cooling and air quality needs. For example, greening can be promoted through various government schemes such as the Nagar Van Yojana, Atal Mission for Rejuvenation and Urban Transformation (AMRUT), and Compensatory Afforestation Fund Management and Planning Authority (CAMPA). Programmes like the Smart Cities Mission advocate for energy-efficient buildings. A closer look at the implementation of these schemes could yield significant benefits.

India must shift from a narrative of isolated, seasonal challenges — polluted winters and overheated summers — to a year-round strategy that helps the vulnerable adapt as well as reduces the impacts of both heat and air pollution.

Annanya Mahajan is a senior research associate and Tamanna Dalal is a research associate at Sustainable Futures Collaborative.

Banner image: Smoke from a factory shot around sunset time. Image by Spykster via Flickr (CC BY 2.0).

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Priyanka Shankar Editor

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Air PollutionEnvironmentIndia

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