of extreme temperatures have led to thousands of deaths since the 1990s, largely in rural areas where basic infrastructure is poor.
R.K. Jenamani, director of the meteorological office in Delhi, said his research did not point to any long-term trend of rising temperatures.
But a combination of urbanisation, extensive use of concrete and more cars did appear to be changing microclimates within and near cities, exacerbating the impact of heatwaves, he said.
Temperatures were rising faster earlier in the day and staying higher for longer in congested built-up areas, he said.
The World Bank warned in a report last year that parts of India were rapidly becoming "heat-islands", and that urban planners needed to act to counteract the dangers.
"We are witnessing more serious and more extreme events," said Anumita Roychowdhury at India's Centre for Science and Environment (CSE), warning about the impact on public health.
The heatwave has led to a jump in deadly ozone pollution in Delhi to levels that exceed government limits, the CSE said, with levels rising up to 315 percent in the city since June 1.
"We need to watch and assess this trend very carefully in this climate-challenged world," said Roychowdhury.