Editor's note: This year marks the 20th anniversary of President Xi Jinping's proposal of the concept that "lucid waters and lush mountains are invaluable assets". To mark the occasion, China Daily is publishing a series of stories on how resources such as mountains, rivers, lakes, forests and farms are being transformed into priceless gifts.

As the early morning sun pierces the mist on Erhai Lake in Southwest China's Yunnan province, Yan Bingqi is already knee-deep in his waders, plucking dead plants from the water.

This is the daily routine for the 59-year-old, who is one of hundreds of cleaners on China's second-highest plateau lake.

Yan said that when he joined the salvage team in 2015, each team member had to collect as much as a metric ton of debris from the water daily. That's how polluted it had gotten.

"Now, with significant changes taking place in Erhai Lake, we only salvage around 50 kilograms daily," he said.

Before 2015, the lake had experienced severe pollution due to rapid, unregulated development in agriculture, urbanization and tourism.

A major shift in policy came after a visit to the area by Chinese President Xi Jinping in 2015, resulting in a comprehensive, multiyear restoration effort for the vital drinking water source and tourist attraction.

Yan said greater environmental awareness has been promoted to those living near the lake, with every household now connected to a sewage network for centralized treatment and fishermen strictly following ecological fishing schedules.