Haidian district intends to remove all high-polluting enterprises by the end of 2017 to improve its air quality, Beijing Morning News reported on Monday. All coal-fired boilers in the district will be removed by the end of 2015, 41 high-polluting enterprises will be moved from the district by the end of 2017, and about 35,000 old vehicles will also be taken out of service by the end of 2017.