BEIJING -?Beijing is offering cash rewards as an incentive for chemical plants that leave the nation's capital. Eighty hazardous chemical plants should be out of the city by 2018, the local work safety watchdog said on Thursday.

The watchdog said it had asked plants to relocate voluntarily and offered a cash bonus, calculated on a set of criteria including the size of the facility, number of employees, tax contributions, safety record and production process. Early applicants will get extra rewards.

The watchdog aims to wave goodbye to 60 plants this year and 20 more between 2017 and 2018. It did not disclose the exact amount of rewards it would pay out.

The removal of chemical plants is the latest measure to rid the capital of polluting industries to improve the environment and optimize the industrial makeup toward more tech-driven and service-based sectors.

Smaller chemical plants with simple production process, poor management and high risk storage will be first to go, the watchdog said, adding that the removal of the facilities should not disrupt the city's supply of hazardous chemical goods.