"Beijing will make every effort in implementing the design of the sub-center of Beijing," Vice-Mayor of Beijing Sui Zhenjiang said at a policy briefing of the State Council Information Office on Friday, stressing that environmental protection would be a top priority of the new sub-center.

The previous chemical plant in Tongzhou will be restructured into a forest park of 11 square kilometers, with a theater, library and museum as supplemental facilities.

The central business district of the sub-center, together with an integrated traffic hub, will connect Tianjin, Tangshan in Hebei province, and the suburbs of Beijing.

"Historical and cultural protection, especially protection of the historical sites in Lucheng town, Tongzhou district, is another major task of the sub-center building," said Sui, adding that intelligent management is a new feature of the sub-center.

Beijing's sub-center, which sits in the east of the capital, aims to accommodate 1.3 million permanent residents by 2035.

The city sub-center will cover 155 sq km and be extended to the whole area of the current Tongzhou district, which has a total of about 906 sq km, according to the plan for the sub-center's development for 2016 to 2035, approved by the Communist Party of China Central Committee and the State Council.