The Environmental Protection Department has rated water quality at 10 beaches 'good' for this weekend, with 19 more 'fair' and four 'poor'.

Compared with last week, water quality at Chung Hom Kok, Deep Water Bay, Hap Mun Bay, Hung Shing Yeh and St Stephen's Beaches was downgraded from good to fair, and Silverstrand Beach was fell from fair to poor.

Seven gazetted beaches - Anglers', Approach, Ting Kau, Casam, Gemini, Hoi Mei Wan and Lido - are closed to swimmers year-round because of poor water quality.

Many beaches are likely to be more polluted than their grades suggest during and after heavy rain. Bathers should avoid swimming at beaches for up to three days after a storm or heavy rainfall.