Across the country record high temperatures of 40 degrees CelsiusFahrenheit) and above have been recorded, including in Shanghai.
China's industrial and commercial centre is sweltering in its longest period of sustained hot weather for more than 50 years, the Xinhua news agency said.
The firing up of so many air conditioners has led to a "grave energy shortage" with the municipal government ordering the suspension of all scenic lighting at night to save electricity.
In rural areas south of the Yangtze River, which is a leading grain production base, more than 6.5 million hectares (16 million acres) of arable land in 11 provinces, including Hunan, Jiangxi, Zhejang and Fujian, have been affected by the drought.
Some 8.65 million urban and rural residents do not have sufficient drinking water, along with 3.89 million head of animals, Xinhua said.
China's communist party leaders have been visiting some of the worst hit areas over the weekend, and urged local governments to step up efforts to help the worst hit farmers.
"Efforts must be made to keep the people from sunstroke, prevent the outbreak of epidemic diseases and guard against fire disasters in the drought-affected areas," vice premier Hui Liangyu said on an inspection tour of central Hunan province.
China has been particularly hard hit by inclement weather this year with at least 3.5 million people also affected by floods.