Mumbai: India Inc's operating cash flow (OCF) weakened significantly in the half year ended September 30, falling to 71.4% of their earnings before interest, tax, depreciation and amortisation 81.8% in the previous six months (excluding banking, financial services and insurance).Free cash flow, meanwhile, plunged to 35.9% of profit after tax (PAT) from 55.1% a year earlier, according to data.