Assertion: The Border Road Organisation (BRO) was established in May 1960 in India
Reasoning: It was established to accelerate economic development and strengthen defence preparedness through the rapid and coordinated improvement of strategically important roads along the northern and northeastern boundaries of the country.

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

Other roads include Border Roads and International Highways. The Border Road Organisation (BRO) was established in May 1960 to accelerate economic development and strengthen defence preparedness through the rapid and coordinated improvement of strategically important roads along the northern and northeastern boundaries of the country. It is a premier multifaceted construction agency. It has constructed roads in high altitude mountainous terrain joining Chandigarh with Manali (Himachal Pradesh) and Leh (Ladakh). This road runs at an average altitude of 4,270 metres above the mean sea level. Apart from the construction and maintenance of roads in strategically sensitive areas, the BRO also undertakes snow clearance in high-altitude areas. The international highways are meant to promote a harmonious relationship with the neighbouring countries by providing effective links with India.