A joint venture between the renewables units of Indian state-run energy group NTPC Ltd (<a href="https://www.bseindia.com/stock-share-price/ntpc-ltd/ntpc/532555/" target="_blank">BOM:532555</a>) and oil and gas company ONGC (<a href="https://www.bseindia.com/stock-share-price/oil-and-natural-gas-corporation-ltd/ongc/500312/" target="_blank">BOM:500312</a>) is moving closer to buying clean energy platform Ayana Renewable Power, the Economic Times reports.