Air pollution such as the wet and dry deposition of nitrogen (N) and sulphur (S) compounds has the potential to cause acidification of ecosystems and impacts on ecosystem biodiversity through both eutrophication and acidification effects. Ozone impacts can also further affect biodiversity of natural vegetation. In South Asia there is still no conclusive evidence of these impacts on natural ecosystems and there is lack of comprehensive studies but there is concern for certain sensitive areas as emissions continue to increase.

Malé Declaration achievements and results

• Modelling studies and training events under the Malé Declaration have demonstrated that there are limited areas in South Asia which may be at risk from acidification from sulphur and nitrogen pollution such as in the Western Ghats, parts of Sri Lanka and eastern India. In the Himalayan regions of India, Bhutan and Nepal soils that are naturally acidic may also be under pressure from acidifying deposition.
• Modelling results suggest that acidification will not be a major issue compared to other air pollution problems in South Asia but further field research is required to determine the real extent of the problem.
• A potentially greater problem to ecosystems and their biodiversity than acidification in South Asia is eutrophication (excessive input of nitrogen and other nutrients). Nitrogen pollution from the transport, industry and agriculture is linked to health impacts, impacts on ecosystems, crops and climate, as well as the formation of ground-level ozone.
• Despite some progress there is still a need for a comprehensive regional assessment of these issues, especially using studies that have been conducted in South Asia.
• The Regional Centre on Crop and Vegetation impacts in Pakistan and on Soil Monitoring in Bhutan are currently being established to oversee co-ordination, harmonization, quality control and reporting of the Malé Declaration ecosystem related impact activities.