Assertion: The first serious attempt of long-term road-development, the ‘Nagpur Plan' could not be implemented in India.
Reasoning: This plan could not be implemented due to lack of coordination among the princely states and British India.

Both Assertion (A) and reasoning (R) are correct, and R is the correct explanation of A.

Road transport in modern sense was very limited in India before World War-II. The first serious attempt was made in 1943 when ‘Nagpur Plan’ was drawn. This plan could not be implemented due to lack of coordination among the princely states and British India. After Independence, twenty-year road plan (1961) was introduced to improve the conditions of roads in India. However, roads continue to concentrate in and around urban centres. Rural and remote areas had the least connectivity by road.