The India Meteorological Department’s forecast of above-normal maximum and minimum temperatures across the country during the pre-monsoon March-May period is a timely alert for State authorities to review their preparedness. Even a marginal rise above the normal will lead to enormous heat stress for millions of Indians, given the deprived conditions in which they live. Moreover, there are distinct groups at particular risk for health-related problems during a heat wave, such as senior citizens and people with pre-existing disease, mental illness or disability, which prevents them from being able to care for themselves. It is the responsibility of governments to ensure that community-level interventions are taken up to help vulnerable groups. The advent of hot weather this year is marked by temperatures rising between 1.6° Celsius and 5° C above normal in States such as Rajasthan, Jammu and Kashmir, Uttarakhand, Uttar Pradesh, Himachal Pradesh and Madhya Pradesh; other northern, central and eastern States also show a small increase from March 1. Of course, Tamil Nadu, Puducherry and parts of Rayalaseema have begun the season with a slight decrease in minimum temperatures, and will possibly have less oppressive temperatures in coming weeks. For most other States, though, the summer of 2018 may pose a public health challenge, for which they must prepare with the experience gained during the many previous heat waves. One scientific estimate of annual mortality attributable to heat waves between 2010 and 2015 ranges between 1,300 and 2,500.
A spike in summer temperatures in India is not new, but some scientists contend that a half-degree rise in average temperature in recent decades has resulted in a higher probability of extreme heat waves and caused a lot of deaths. A heat event thus has serious implications for public health: it can lead to fatal heat stroke in a small percentage of people, while many more could encounter exhaustion, cramps and fainting. It is vital for governments to ensure that all stakeholders, including the health-care system, are prepared to deal with the phenomenon. The World Health Organisation recommends that countries adopt heat-health warning systems, including daily alerts to ensure that people are in a position to deal with adverse weather, starting with reduction of exposure. Water stress is a common and often chronic feature in many States: arrangements should be made to meet scarcity. There is some hope that the southwest monsoon this year will benefit from an expected moderate La Niña condition in the equatorial Pacific, marked by cooler-than-average sea surface temperature. Taking the long-term view, India has to pursue mitigation of greenhouse gases vigorously, since there is a perceived link between increases in average temperature caused by climate change and the frequency and intensity of extreme weather events.
