What is the name of India's highway network linking Delhi, Mumbai, Chennai, and Kolkata?

India's highway network linking Delhi, Mumbai, Chennai, and Kolkata is the Golden Quadrilateral.

The Golden Quadrilateral is a network of multi-lane national highways forming a rough four-sided shape across India. Its four principal cities mark the corners: Delhi in the north, Kolkata in the east, Chennai in the south, and Mumbai in the west. The network spans roughly 5,846 kilometers.

The project formed part of the first phase of India's National Highways Development Project. The National Highways Authority of India implemented the work, which was launched in 1999 and declared complete in 2012 after delays involving land acquisition, contracting, and construction. It was designed to improve travel times, freight movement, market access, and links among major economic centers.

A common mix-up is the Golden Triangle, a tourism circuit usually referring to Delhi, Agra, and Jaipur. The East-West and North-South Corridors are separate highway programs that connect different parts of India. The Golden Quadrilateral is a network rather than one single road with one continuous highway number.