Beijing issued this summer's first heat alert on Sunday as the maximum temperature in the Chinese capital soared above 40 degrees celsius.

Under the orange alert, which is the second highest, workers who are exposed to high temperatures must reduce their working hours.

Beijing Meteorological Service attributed the heat to the lack of rain.

The intense heat also caused heavy ozone pollution, according to the city's environmental watchdog.

The temperature is expected to drop significantly on Wednesday, according to Beijing Meteorological Service.