Mitigation of carbon footprints in compression ignition (CI) engines can be achieved using biofuels (carbon neutral and carbon dioxide (CO2) sequestration effects), with oxygenates and effective post-combustion capture systems. The present study focuses on the net reduction of CO2 emissions through the combination of karanja oil methyl ester (KOME), orange oil (ORG), oxygenates blended fuel and zeolite-based post-combustion capture system (ZPCS) in a single cylinder CI engine. KOME emitted higher CO2 emissions as compared to the diesel. Blending equal volume of ORG with KOME reduced CO2 emissions further by 27% compared to KOME but still higher compared to diesel by 11%, at 100% load condition. Four oxygenates, namely methanol (M), ethanol (E), n-butanol (B) and n-pentanol (P) were blended 20% by volume with the KOME-ORG. KOME-ORG + M20 emitted minimum CO2 compared to other oxygenate blends due to stoichiometric carbon balance, about 38% less compared to KOME nearly reaching diesel emission characteristics at 100% load. Additionally ZCPS was placed in the exhaust line and tested with all oxygenate blends with KOME-ORG, methanol blend led to 65% reduction in CO2 emissions compared to KOME and 53% reduction compared to diesel, at 100% load. (C) 2018 Elsevier Ltd. All rights reserved.