A sever heatwave continued to batter Pakistan’s largest city of Karachi for a third week, filling hospitals with patients and morgues with boides, officials and rescuers said on Thursday.

More than 50 people have died so far due to heatstroke since the start of the latest wave last month, police spokeswoman Summiya Syed said.

Dozens of new victims were brought to the city’s largest Jinnah Postgraduate Medical Centre on Wednesday, the hospital’s spokesman Hassan Ali told dpa.

The heat index – a combination of the temperature and humidity – rose to 55 degrees Celsius on Wednesday, the highest level ever recorded in the coastal city of more than 20 million people, chief meteorologist Sardar Sarfraz said.

“This is unbearable in many ways. This happens because the breeze from the sea has stopped and humidity has risen to 55%,” he said.

A charity that runs the largest ambulance service in the city and several morgues said the actual death toll might be much higher than the numbers officially known.

Rescue workers from the Edhi Foundation charity collected more than 140 bodies on Wednesday against the usual daily average of between 30 and 40.

“This has been a trend since the heatwave started. Our daily number goes beyond 100 every day,” the charity’s spokesman Mohamed Amin told dpa.

It is the second heatwave that has hit the climate-vulnerable South Asian nation this year. Temperature rose beyond 50 degrees in several cities during the first one in early June.