Twenty-three beaches have been rated 'good' in the Environmental Protection Department's latest water quality gradings. Nine other beaches are 'fair' and one is 'very poor'.

Compared with last week, water quality at Shek O and Stanley Main Beaches have been downgraded from 'good' to 'fair', while Ma Wan Tung Wan Beach has been changed from 'fair' to 'very 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.