Latitudinal spatial variations in aerosol optical properties are analysed over the Indo-Gangetic Plains (IGP) of northern India to a highland location in the central Himalayas during pre-monsoon (April to June) of the 2008 and 2009. Measurements of aerosol optical depth (AOD) were performed using ground based sun photometers at four sites in different aerosol environments. The AOD values increase from Kanpur (a major industrial city in central IGP) to Nainital. Further, aerosol size varies spatially with the dominance of coarse mode aerosols at Kanpur (due mainly to mineral dust transport) compared to fine mode dominated aerosols at Nainital. The spectral variation of single scattering albedo suggests the dominance of dust from IGP to Himalayan foothills (Pantnagar) during the pre-monsoon. More absorbing aerosols are retrieved at Pantnagar than Kanpur. The short wave aerosol radiative forcing (ARF) is estimated and the optical properties of aerosols (e.g. AOD, SSA, asymmetry parameter) are calculated and will be discussed.