The most urgent environmental problem that Southeast Asia faces periodically is the haze caused by land and forest fires. Even before the severe haze episode of 1997-98, ASEAN had taken some cooperative actions to prevent the haze and mitigate its impact, mostly as prescribed in the 1995 ASEAN Cooperation Plan on Transboundary Pollution. These included the strengthening of the ASEAN Specialized Meteorological Centre in Singapore, work towards a common air-quality index, and a fire danger rating system. In response to the 1997-98 episode, ASEAN adopted the Regional Haze Action Plan, a detailed set of measures for preventing land and forest fires and mitigating their effects, including fire-fighting arrangements and the education and involvement of local communities. In 2002, ASEAN concluded the Agreement on Transboundary Haze Pollution formalizing the parties' commitments. The agreement entered into force in November 2003. In other environmental matters, ASEAN has designated twenty-seven protected areas as ASEAN Heritage Parks, launched a programme for water resource management, set up an ASEAN Centre for Biodiversity, established a project to restore degraded forests and ecosystems, agreed on a set of marine water-quality criteria, and adopted a programme on environmental education and public awareness.