water pollution index

例句：

1. 1.The city's water pollution index has been on the rise recently.
   该市的水污染指数最近一直在上升。
2. 2. The government is working hard to reduce the water pollution index in the country.
   政府正在努力降低该国的水污染指数。
3. 3.The water pollution index is a crucial indicator of environmental health.
   水污染指数是衡量环境健康状况的关键指标。