Give the name of the mega-highway connecting four cities?

The mega-highway connecting the four metropolitan cities of Delhi, Mumbai, Chennai, and Kolkata is the Golden Quadrilateral. It is the longest highway project in India. It connects other important cities like Ahmedabad, Bengaluru, Bhubaneswar, Jaipur, Surat, Varanasi, Agra, Mathura, and many others.