Thus, a number of studies have been carried out so far on the glacier mapping and change detection of Himalayan and other ranges glaciers using satellite images in digital or analogue format. In most of these studies, mapping has been done based on digitization of glacier extents using visual interpretation technique. Visual interpretation technique is subjective and depends on the spatial and radiometric resolution of the sensor, scale of mapping and experience of analyst, thus causing uncertainties in the mapping accuracy. The interpretation becomes more debatable when glaciers are heavily debris covered on their ablation zones and interpretation becomes tedious. Therefore, in order to see the effect of climatic variations on glaciers, debris free glaciers should be given the priority. In view of this, it has been attempted to find changes in extents of debris free glaciers using IRS LISS III images of 2001 and 2016 during ablation time. This has been done using an algorithm based on Normalized Difference Snow Index (NDSI). It has been confirmed that there is no significant retreat of debris free glaciers (approx. 0.75 % loss in area for 50 debris free glaciers) between 2001 and 2016.
