Ozone concentrations in the climatically important tropical troposphere show two regions of high values and high intraseasonal variability: the Tropical Atlantic and the Tropical Indian Ocean. The boreal late-winter season's variations have been especially hard to explain. During the Indian winter monsoon in February to March,1999, the INDOEX period, there was large temporal variability of tropical tropospheric ozone (TTO); maximum ozone amounts varied from 20 Dobson Units to 45 Dobson Units. We explain this variability using wind, Outgoing Longwave Radiation (OLR), TTO from the Total Ozone Mapping Spectrometer (TOMS) and also ozonesondes from the Indian Ocean Experiment (INDOEX) measurements. Our preliminary analysis suggests that the TTO over the Indian Ocean is closely correlated with Madden-Julian Oscillation (MJO) through a common, but intermittent, sequence of transport steps. This work will describe in detail the ozone build-up and transport mechanism during the INDOEX period.