With the growing energy and food needs in south Asia, controlling emissions of different air pollutants which affect air quality and atmospheric processes is a major challenge. This needs a systematic long term monitoring of the air composition change and the concentration trends of  selected pollutants in south Asian region. Air mercury is one of the highly toxic metals in the atmosphere. It has severe health impacts and environmental consequences. In spite of this fact, very few studies are reported on atmospheric mercury in south Asia. In a study from our group, the volume weighted mean (VWM) of HgT concentration in rain water in Delhi-NCR was recorded as 3.31 and 4.73 mg/L at the urban site during monsoon and winter season respectively, while VWM HgT concentration was as 1.21 and 2.53 mg/L at the rural site.  The average PM₁₀ particulate (mercury HgP) level was the highest (1.81  ng m-³) at a site near the thermal power plant.

South Asian region is a significant contributor to the global share of atmospheric Nr. In India, the total deposition of N (3.61 Tg) is reported to be 57% of the total emissions indicating a need of further research in order to explain the Nr distribution in different phases. It has been reported that the wet deposition fluxes of NH₄⁺ and NO₃^- are increased remarkably at Delhi during past two decades which can be attributed to the increasing urbanization and industrialization in the city. Abundance and phase distribution studies show that particulate NH₄⁺ is noticed lower than gaseous NH₃ as reported at Delhi during all the seasons. Information available from other south Asian countries about atmospheric Nr is very limited. It has been realized that there is a need of a strong network of reactive nitrogen monitoring across south Asia inclduing dry deposition of Nr species sucha as NOx and NH_3. The project GCRF-South Asian Nitrogen Hub will be focusing upon Nr species during next five years. However, there is need to cover south Asia for Hg measurements and I see a possibility for Hg network through the new boundaries of NADP extending to south Asia.