An index gauging the environment for working women in India gives Sikkim the top ranking and Delhi the lowest among states and Union Territories.

The index, compiled by Nathan Associates Inc. and the Center for Strategic & International Studies, a Washington, D.C., research institution, examined four criteria: legal restrictions on working hours in three sectors; responsiveness of the justice system to crimes, including harassment, against women on the job and during their commutes; women as a percentage of all workers; and official incentives for female entrepreneurs.

Tiny Sikkim in the northeast was among states that have removed all restrictions on women working at night in manufacturing, retail, and information technology. Sikkim scored 29.9 out of a possible 40 for the combined indexes and did not receive a higher score because it had no rating for official incentives. Telangana and Puducherry ranked second and third at 28.5 and 28.6, with ratings in all four categories. Delhi received an overall 8.5. Assam, Jammu & Kashmir, and West Bengal all received ratings of less than 10.

Removing obstacles to women’s workforce participation will help India’s economy, which is why Nathan and the center’s Wadhwani Chair in U.S.-India Policy Studies examined the issue in their joint ”Breakthrough” series of indexes. The series examines reforms that advance economic development along with business and economic ties between the U.S. and India.

Only 24 percent of India’s workforce was female in 2014, compared with participation rates exceeding 40 percent in the six economies larger than India’s—China, Japan, France, Germany, the United Kingdom, and the United States, according to data from the World Bank and International Labor Organization.

The inaugural Wadhwani/Nathan Breakthrough Index, published in July, ranked industrial land policy in India’s 29 states. Some areas of future coverage include clean energy, ease of doing business, entrepreneurship, and government efficiency.

Nathan has conducted pioneering analysis of economic policies, competition, and regulation in India, where the U.S.-based firm has offices.The indexes are based on official data, occasionally supplemented by media sources determined to be reliable.

Nathan also specializes in gender integration.