The distribution and budget of tropospheric NO x over Asia, especially India, are examined using the global 3D chemistry-meteorology model MATCH-MPIC and GOME NO 2 columns. Enhanced abundances of NO 2 over China and northeast India are reproduced by the model, as are the pronounced maxima during biomass burning periods, though somewhat underestimated. The mean NO 2 column over India is also reproduced, though the model has trouble with the seasonal cycle for unknown reasons. Model sensitivity tests for the Indian region indicate that the scaled sensitivity to changes in the local NO x source is 60-70% for lower tropospheric NO x and is only 10-25% for tropospheric O 3 , indicating that moderate reductions or increases in current NO x emissions are not expected to lead to large changes in regional O 3 levels. In the upper troposphere, during winter nearly all of the NO x comes from remote sources, while in summer deep convection causes the upper troposphere to become sensitive to local surface emissions (~40-50% scaled sensitivity) and lightning NO x production (~10-20%). The regional lifetime of NO x estimated for India, based on MATCH output is about 15-23h, comparable to the lifetime of NO x over China (14-21h), while over Indonesia (23-43h) and North Asia (21-47h), it is longer and highly seasonal. Implications of these results are discussed.