Representative photo: Ant Rosetzky/Unsplash. Carbon dioxide levels have hit a record high yet again despite the slowdown caused by the coronavirus lockdowns globally. Based on estimates by the GHG Platform, heavy industries comprising cement, steel, chemicals, and aluminium and heavy-duty transport such as shipping, trucking, and aviation are responsible for more than a third of the carbon dioxide emissions in India. Notwithstanding efforts to decarbonise, these emissions are projected to increase by more than two to three times by mid-century. These heavy industries are considered hard to abate because they depend on fossil fuels for energy and as feedstock in their production processes. The use of coke for iron-ore reduction in blast furnaces, coal for clinker formation in a cement kiln and crude oil as the primary feedstock in petrochemicals are a few examples. In addition to emissions due to combustion of fossil fuels, these industries also produce process emissions during physical and chemical conversions of raw materials. The conversion of limestone to clinker and the depletion of carbon anodes in the production of aluminium are cases in point.