India could witness deadly heatwaves if the planet's temperature goes up by two degrees Celsius, according to a report released on Monday by the UN's Intergovernmental Panel for Climate Change (IPCC). "At +2°C warming, Karachi and Kolkata could expect annual conditions equivalent to their deadly 2015 heatwaves (medium confidence)," the report said.

Avoiding global climate chaos will require a major change of society and the world economy that is "unprecedented in scale," the IPCC said in the report that warns time is running out to avert disaster. "At +1.5°C, twice as many megacities as present such as Lagos in Nigeria and Shanghai in China are likely to become heat stressed, potentially exposing more than 350 million more people to deadly heat stress by 2050," the report further adds.