LHASA -- Lhasa, capital of Southwest China's Tibet autonomous region, has been promoting online systems to improve supervision on pollution-intensive enterprises, according to the local environmental bureau.

So far, 61 companies have installed online automatic monitoring equipment, and 48 of them have had their devices connected to the supervision system of the city's environmental bureau.

The devices, set up near the pollution sources in the companies, can monitor water and air qualities as well as obtain the real-time view of the sources.

Any abnormalities in the monitoring data will trigger an alert, and a text message will be sent to the law enforcement to help improve the supervision and emergency response capabilities, according to the environmental bureau.

Air quality remained high in Lhasa last year, with 99.7 percent of all the days having good air quality, and the water was up to standard in all major rivers and lakes and four drinking water sources in the city, according to local statistics.