Which of the four big metro cities of India are connected by the Golden Quadrilateral ?

Delhi - Mumbai - Chennai - Kolkata

Golden Quadrilateral : It comprises construction of 5,846-km long 4/6 lane, high density traffic corridor, to connect India’s four big metro cities of Delhi-Mumbai-Chennai-Kolkata. With the construction of Golden Quadrilateral, the time, distance and cost of movement among the mega cities of India will be considerably minimised.