The infra major had signed a binding share purchase agreement (SPA) with Cube Highways for its 100 per cent stake in the toll road.
Accordingly, the company will receive an enterprise value of Rs 3,600 crore, including equity of around Rs 1,700 crore.
"Reliance Infrastructure will utilise 100 per cent of proceeds only for debt reduction," the company said in a statement.
"With this single transaction of the Delhi-Agra toll road, debt of Reliance Infrastructure will reduce by over 25 per cent to less than Rs 5,000 crore," it said.
Cube Highways and Infrastructure III Pte Ltd. is a Singapore-based company formed by Global Infrastructure Fund - I Squared Capital and a wholly-owned subsidiary of the Abu Dhabi Investment Authority.
"This sale will significantly reduce the debt of Reliance Infrastructure on its path to becoming a 'Zero Debt' company," Reliance Infrastructure CEO Punit Garg was quoted as saying in a statement.
"Reliance Infrastructure has once again proven its ability by efficiently operating the showpiece Indian infrastructure of the 180-km six lane Delhi-Agra toll road."
The development comes a day after RInfra announced that it will construct a 17.17 km-long Versova-Bandra Sea Link (VBSL) at a cost of Rs 7,000 crore.
The project - to be developed by RInfra in partnership with Italy's Astaldi S.p.A. - was awarded on June 24 and shall be commissioned within the next five years.
( With inputs from IANS )