GUANGZHOU - Construction on a power transmission line to distribute power from southwest China's Yunnan province to the Pearl River Delta region in Guangdong province began Wednesday, in a move to ease its power shortages and alleviate the worsening smog problems.

The ultra-high-voltage direct current (UHV DC) power transmission line, which is 1,959 kilometers long, links Jianchuan county in Yunnan with Bao'an district of Shenzhen city. It is the longest power transmission line China Southern Power Grid has constructed.

With a total investment of more than 22 billion yuan ($3 billion), the project is scheduled to send power in 2017. When it is completed, it can transfer 20 billion kilowatt-hours of electricity each year to Guangdong, an equivalent of 25 percent of power used by Shenzhen annually.

Zheng Shanjie, deputy head with the National Energy Administration, said the project can stabilize low-carbon economic growth in the Pearl River Delta region.

The delta region, a manufacturing center, includes cities such as Guangzhou, Shenzhen, Dongguan, Foshan and Zhongshan.

The line will help Pearl River Delta region cut coal consumption by 6.4 million tonnes, emissions of carbon dioxide and sulfur dioxide by 16 million tonnes and 123,000 tonnes respectively every year.

This project, together with another 11 electricity transmission lines which aim to send power from the west to densely populated east, is part of China's action plan to reduce coal consumption and control air pollution.