"Starts With Simple Signs Like...": What Doctor Said On Heat Stroke

Experts have asked people to prepare to accept the real possibility of seeing record high temperatures. The comments come on a day a weather station in Delhi reported 52.3 degree Celsius - the highest ever in India. The weather office, however, said the temperature sensor at the Mungeshpur automatic weather station is being checked to see if the sensor is working properly.

"Records keep getting broken every month, be it heatwaves, lightning, thunderstorms... All this will continue to happen because of another active contribution from greenhouse warming and climate change," KJ Ramesh, former Director General of Meteorology of India Meteorological Department (IMD), told NDTV.

"Incrementally, some parts of urban areas will be hotter than the other due to heat island effect, and reduction of green cover will increase localised hotspots of extreme heat. That's how we are responsible for land cover changes..." he said.

Heat island effect is the result of replacing natural land cover with heat-absorbing surfaces like buildings, pavement, and other infrastructure.

"Emitting air-conditioners add additional heat. 2 degree Celsius of additional heat is added by ACs, we should not forget this," Mr Ramesh added.

Dr Vivek Nangia of pulmonology at Max Super Speciality Hospital said when exposed to very high temperature, the body loses fluid and electrolytes.

"As a result, it will start with simple signs like heat rash, going on to people developing heat cramps, body ache, getting tired by end of the day. It could worsen to what is called heat exhaustion where people could develop headache, nausea dizziness, weakness, immense thirst, heavy sweating... if the heat is too much, people may black out and just collapse. Blood pressure can drop," he said.

"The last stage is heat stroke, which can be fatal at times. When you have a heat stroke, that's the point the patient has high fever, profuse sweating, unresponsive, can be fatal," Dr Nangia said.

Delhi's primary weather station Safdarjung observatory recorded a maximum temperature of 46.8 degree Celsius, highest in 79 years.

The IMD issued a red alert health notice for Delhi, with an estimated population of more than 30 million people. The alert warns there is a "very high likelihood of developing heat illness and heat stroke in all ages", with "extreme care needed for vulnerable people".

India is no stranger to searing summer temperatures, but years of scientific research have found climate change is causing heatwaves to become longer, more frequent and more intense.