Which of the following statements is correct?

a- The main roads which are constructed and maintained by the Central Government are known as the National Highways.

b- The length of the National Highways has increased from 19,700 km in 1951 to 1,36,440 km in 2020.

Both statements are correct.

The main roads which are constructed and maintained by the Central Government are known as the National Highways. These roads are meant for inter-state transport and movement of defence men and material in strategic areas. These also connect the state capitals, major cities, important ports, railway junctions, etc. The length of the National Highways has increased from 19,700 km in 1951 to 1,36,440 km in 2020. The National Highways constitute only about 2 per cent of the total road length but carry 40 per cent of the road traffic.