Clean air and green world are the requirements of today. Transportation powered by conventional fossil fuels is the largest single source of air pollution. To improve the air quality by reducing of vehicle exhaust emission levels, oxygenates has been added to petrol since 1990 as per Clean Air Act Amendments. The present report is an analysis of petrol for the presence of oxygenates using FTIR-ATR technique in the mid-IR region. Petrol samples for analysis were collected from different filling stations within Aizawl city. Out of 9 samples tested including extra-premium (XP) grade, only one sample is found to contain oxygenate, namely, methyl tertiary-butyl ether (MTBE). The presence of the oxygenate in petrol can be identified from its distinct IR absorption bands at 1203, 1085 and 852 cm-1 due to the C-C and C-O vibrational modes of the molecule. IR mode assignment of the fuel in the 650-3750 cm-1 is also discussed and presented.