It's June, which means more people will be heading for the water. But as recently as a few years ago, people were unable to swim in China's largest downtown lake. For decades, the East Lake in Wuhan, in central China's Hubei Province, suffered from soil, water, noise and air pollution. But now, people are once again using it as a place to cool off, and even have swimming contests. Xia Ruixue reports.

On Sunday, the annual Wuhan Swimming Marathon kicked off at the East Lake, in Wuhan, Hubei Province. It attracted 1,800 participants including 73 professional swimmers and 1,727 swimming fans. Many participants said they saw big fish swimming with them.

SWIMMER "I swam in the East Lake when I was a child. It was very very clean. Now the water quality is like it was back then."

In fact, ten years ago, East Lake, China's largest downtown lake, was not like what it is today. Wuhan used to be a heavy manufacturing base, which in turn, brought it a great deal of pollution to the lake. The outbreak of blue-green algae occurred many times. Dead fish were seen everywhere.

ZENG BIE, VICE DIRECTOR ADMINISTRATION COMMITTEE OF EAST LAKE "For the past 30 years, we kept curbing the pollution. We started from monitoring all the sewage outlets and making sure no polluted water is discharged into the lake."

In 2015, the local government started building a long greenway network encircling the East Lake. Now the 102-kilometer belt of green space has helped improve the water quality and also provides a pleasant place where people can relax.

CHILD "I love coming here. I can see frogs and mandarin ducks swimming in the lake."

WANG HONGZHU, RESEARCHER INSTITUTE OF HYDROBIOLOGY, CHINESE ACADEMY OF SCIENCES "The water in the lakes will finally go to the Yangtze River. If we improve their water quality, it will help the Yangtze River get cleaner too."

East Lake's average water quality had long been at Grade V or worse by Chinese standards before 2008; the lowest quality grade in China's five-tier system. Now its water quality has been at Grade 2 for 5 months, the best level in the past 40 years. It's now ready for the sailing competition of the 7th Military World Games this October.

XIA RUIXUE WUHAN "Wuhan is known as 'the city of a hundred lakes'. Its water quality has gotten better in recent years, but the fight must go on. And that will require more time and effort. Xia Ruixue, CGTN, Wuhan, Hubei Province."