These eight segments comprise 40.27 percent of the weight of items included in the Index of Industrial Production (IIP). : These eight segments comprise 40.27 percent of the weight of items included in the Index of Industrial Production (IIP). Eight infrastructure sectors of coal, crude oil, natural gas, refinery products, fertilisers, steel, cement and electricity had grown by 5 percent in October 2017. Crude Oil production declined by 5 percent, Natural Gas production by 0.9 percent and fertilizers production by 11.5 percent in October.