In the first week of June 2018, a global dust storm started growing on Mars and it has grown to its mature phase by the first week of July, 2018. The growth of the global dust storm can be seen in the bottom panel of Figure 1 which shows the 9.3μm infrared absorption column dust optical depth (CDOD) near the Mars surface. Larger values of CDOD indicate more dust on Mars. During this time, MOM spacecraft observed the evening side of Mars by diving down to altitudes as low as 155 km. The Mars Exospheric Neutral Composition Analyser (MENCA) instrument, which is a mass spectrometer on MOM, measured the neutral densities of the Mars’ thermosphere (which lies between 100 and 200 km). By analysing these measurements, scientists at the National Atmospheric Research Laboratory, Gadanki have found that Mars upper atmosphere is undergoing warming and expansion. As the dust storm slowly engulfs Mars over a month period (black dotted curve in the bottom panel of Figure 1), scientists have found that the neutral densities in the Mars thermosphere increased significantly (blue dots in the top panel of Figure 1). Such an increase is also confirmed by the MAVEN mission, which was simultaneously measuring the Martian thermosphere on the morning side (blue dots in the middle panel of Figure 1). Note that, to bring out the dust storm effects clearly, nominal local time variations of the densities are constructed from MAVEN measurements and are removed from the densities measured during the dust storm time. The Ar densities measured by MOM on the evening side are always larger than those measured by MAVEN on the morning side (Figure 1). Such a difference is mainly due to the warming on the evening side and cooling on the morning side, caused by atmospheric circulation.