China's scorched southwestern regions extended curbs on power consumption as they deal with dwindling hydropower output and surging household electricity demand during a long drought and heatwave.

State weather forecasters issued a heat "red alert" for the 11th consecutive day, as extreme weather continues to play havoc with power supplies and damage crops.

They also raised the national drought alert to "orange" - the second-highest level.

The drought has already "severely affected" mid-season rice and summer corn in some southern regions, the ministry of agriculture has said.

The National Meteorological Centre said as many as 62 weather stations, from Sichuan in the southwest to Fujian on the southeastern coast, recorded record temperatures yesterday. The situation could improve starting on Wednesday as a cold front moves into China via Xinjiang.

The region of Chongqing, which hit temperatures of 45 degrees Celsius late last week, announced that opening hours at more than 500 malls and other commercial venues would be shortened starting today to ease power demand.

In neighbouring Sichuan province, a major hydropower generator, authorities also extended existing curbs on industrial power consumers until 25 August, financial news service Caixin said. Power generation in Sichuan is at just half the normal level.

Lights were turned off at the Chunxi Road pedestrianised shopping street in Chengdu

It cited firms in the battery industry as saying that industrial power users in the cities of Yibin and Suining had been told to remain closed until Thursday.

Toyota Motor Corp gradually resumed operations at its Sichuan plant in China today using a power generator after suspending operations last week, the company's spokesperson said.

Other regions have also sent 50 emergency power generating vehicles to Sichuan since last Thursday to help alleviate shortages, the Global Times newspaper said.

Several plants in Sichuan and Chongqing, including those of top battery maker CATL and the electric vehicle giant BYD, have been only able to partially operate in recent weeks because of power shortages.

A source familiar with the matter said that CATL's Yibin plant makes battery cells for Tesla, and that there were concerns that continued disruptions could eventually affect the US carmaker.

People use the Han River in Wuhan to cool down

However, a second source said there was no sign of an impact so far, with production at Tesla's Shanghai plant unchanged.

Shanghai, which was criticised on China's Twitter-like Weibo service for its use of electricity generated in Sichuan, imposed its own consumption restrictions today turning off decorative lighting on the riverside Bund area and parts of the financial centre of Lujiazui for two days.

Firms will be encouraged to "stagger" power consumption to reduce peak loads. Some outdoor construction projects will be suspended, the official Shanghai Daily said.

Important agricultural regions have also been warning of the impact on crops, with Henan province saying more than a million hectares of land have been affected by drought so far.

About 2.2 million hectares across the Yangtze basin have been affected, according to the Ministry of Water Resources.