The proportion of India's GDP contributed by the ___________ sector increased in the period from 11.8 per cent in 1950-51 to 24.6 per cent in 1990-91. 

The correct answer is industrial.Key Points

• The industrial sector contributed significantly to India's GDP, increasing from 11.8% in 1950-51 to 24.6% in 1990-91.
• This growth was due to the government's focus on industrial development during the post-independence period.
• The industrial sector includes manufacturing, mining, and construction industries.
• The growth in the industrial sector led to a decrease in the share of the agricultural sector in India's GDP.
• The services sector also saw significant growth during this period, but it was not as significant as the industrial sector.​

Additional Information

• The defence sector is not directly related to GDP contribution.
• The services sector did see significant growth during this period, but it was not as significant as the industrial sector.
• However, it is still an important contributor to India's GDP.
• The agricultural sector saw a decrease in its share of India's GDP during this period due to the growth in the industrial and services sectors.
• However, it still remains an important sector for India's economy.