NEW DELHI, Aug. 21 -- Annual growth in eight key infrastructure sectors, as measured by the combined Index of Eight Core Industries (ICI), slowed marginally in July, according to data released by the ministry of commerce and industry on Wednesday. The July reading came in at 2%, down from 2.2% in June. On a month-on-month basis, the index contracted by 0.7%, an improvement from June's 1.7% contraction. The eight sectors in the index are coal, crude oil, natural gas, refinery products, fertilisers, steel, cement, and electricity. They comprise 40.3% of the weight of items in the Index of Industrial Production (IIP). The slight decrease in July was mainly on account of contractions in the refinery products and coal sectors, which was offset b...