Story highlights Shanghai experiences its hottest July in at least 140 years

Dozens of people have died from heat-related causes in recent weeks, state media report

A meteorological agency has issued its second-highest national alert

Local authorities are resorting to cloud-seeding methods to try to induce rain

Record-breaking temperatures have been searing large swaths of China, resulting in dozens of heat-related deaths and prompting authorities to issue a national alert.

People are packing into swimming pools or taking refuge in caves in their attempts to escape the fierce temperatures. Local governments are resorting to cloud-seeding technology to try to bring rain to millions of acres of parched farmland.

The worst of the smoldering heat wave has been concentrated in the south and east of the country, with the commercial metropolis of Shanghai experiencing its hottest July in at least 140 years, according to state media.

Temperatures in the sprawling city of 23 million inhabitants reached 35 degrees Celsius (95 degrees Fahrenheit) or higher on 25 days in July, the state-run news agency Xinhua reported Wednesday. More than 10 people died from heatstroke in Shanghai during the month, it said.

But the brutal temperatures aren't confined to the Shanghai region.

"About 19 provinces and regions are experiencing scorching heat, covering more than 3 million square kilometers, almost a third of the country," He Lifu, chief weather forecaster at the National Meteorological Center, told the English-language newspaper China Daily.

Heat wave - how hot is it?

The China Meteorological Administration issued its second-highest national heat alert on Tuesday, China Daily reported, adding that the highest alert has never been used.

Photos carried by state media showed people frying food like eggs, shrimp and bacon in pans placed on the road surface in some cities.

In Shanghai, the heat was being blamed for mounting numbers of dead fish in ponds and rivers, reported Shanghai Daily, an English-language newspaper.

Some of the highest temperatures were clocked in and around the eastern city of Hangzhou, about 100 kilometers southwest of Shanghai.

The thermometer went above 40 degrees Celsius (104 degrees Fahrenheit) in Hangzhou on six out of seven days in the past week, state media reported. In the district of Xiaoshan, it reached 42.2 degrees Celsius (about 108 Fahrenheit) on Tuesday, the highest temperature recorded for the area.

Seven cities and counties in the surrounding province of Zhejiang used cloud-seeding techniques on Tuesday to bring rain to drought-hit farmland, China Daily said.

Forecasters say the aggressive heat is likely to continue into the middle of August.