TAIPEI (Taiwan News) — Severe river pollution in Taiwan has dropped 96% since 2002, according to long-term monitoring data from the Ministry of Environment.

Rivers monitored at 66 sites in 2002 were classified as severely polluted. Last year, only two sites showed severe pollution, CNA reported Wednesday.

Officials attributed the improvement to expanded wastewater treatment and nationwide on-site purification facilities. Working with local governments, the ministry has built 92 on-site purification facilities across the country.

Taiwan evaluates river water quality using the River Pollution Index, which measures indicators such as dissolved oxygen and ammonia. Rivers are categorized as unpolluted or slightly polluted, mildly polluted, moderately polluted, or severely polluted, according to the Water Quality Protection Web.

Many of these sites also serve as public spaces for environmental education and community engagement. In Taoyuan, Ruixing Wetland features seven ecological ponds that protect rare native soybean species.

The site is popular with birdwatchers and cyclists, with carefully planned vegetation that balances sunlight and shade. A mix of emergent, floating, and submerged plants helps maintain ecological stability, while bird perches and eco-friendly installations support habitat restoration and educational activities.

In Tainan, the purification project at Yuejin Harbor removed long-standing odors and revitalized the waterfront. Surveys have recorded waterbird species including red-crowned water chickens, kingfishers, white wagtails, great egrets, and night herons.

The area now hosts an annual lantern festival. It also features landscaped public spaces, such as walking and cycling paths and rest areas.

Near Taichung Station, two gravel-based purification facilities treat about 36 billion kilograms of wastewater each day. The surrounding area combines infrastructure with public amenities, including a water-themed playground and a corridor highlighting local history.