This document contains the presentation by S. Das et al, Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai and University of Iowa, Iowa City, USA on “Data assimilation using optimal interpolation: Correcting chemical transport model predictions with satellite observations” during Second National Research Conference on Climate Change, organized by the Centre for Science and Environment, IIT Delhi and IIT Madras on November 5-6, 2011 at New Delhi.