URUMQI, May 11 (Xinhua) -- Senior Chinese leader Zhou Yongkang has encouraged more Chinese companies to develop their businesses in the country's northwestern Xinjiang Uygur Autonomous Region to help boost the region's economy.

Zhou, a member of the Standing Committee of the Political Bureau of the Communist Party of China Central Committee, made the remarks on Tuesday during a seminar held in Xinjiang.

Representatives from companies at central, provincial and local levels attended the seminar, which was held to allow them to introduce future programs and projects that will assist Xinjiang's development.

Applauding these companies' efforts to promote Xinjiang's economic progress, Zhou said that he hopes more companies will actively join in helping to develop the region.

Zhou urged state-owned companies to take a leading role in the effort, saying these companies should make greater efforts to bolster the region's economic growth and bring in more job opportunities for local people.

He expressed the hope that these companies will turn Xinjiang's wealth of oil, coal and natural gas reserves into an economic advantage, noting that environmental protection should be kept in mind as well.

Zhou called for putting an end to unauthorized mining in China, stating that the practice of "polluting first and cleaning up later" should be avoided.

Zhou also pledged to create favorable policies for companies that wish to develop their businesses in Xinjiang, such as tax breaks and financing opportunities.

In accordance with support policies created last year, Xinjiang will be the first Chinese region to reform its resource taxes. Crude oil and natural gas will be taxed by price instead of volume, according to the policies.

Under another tax policy that has yet to be introduced, qualified companies in impoverished areas of Xinjiang will be exempted from paying income taxes for two years and given a 50 percent income tax reduction for another three years.