in Karnataka, led an armed rebellion against the British in response to the Doctrine of lapse. Rani Lakshmi Bai, the Queen of Jhansi, led the Indian Rebellion of 1857 against the British. She is now widely considered as a national hero. Begum Hazrat Mahal, the co-ruler of Awadh, was another ruler who led the revolt of 1857. She refused deals with the British and later retreated to Nepal. The Begums of Bhopal were also considered notable female rulers during this period. They were trained in martial arts. Chandramukhi Basu, Kadambini Ganguly and Anandi Gopal Joshi were some of the earliest Indian women to obtain a degree. In 1917, the first women's delegation met the Secretary of State to demand women's political rights, supported by the Indian National Congress. The All India Women's Education Conference was held in Pune in 1927, it became a major organisation in the movement for social change. In 1929, the Child Marriage Restraint Act was passed, stipulating fourteen as the minimum age of marriage for a girl. Mahatma Gandhi, himself a victim of child marriage at the age of thirteen, he later urged people to boycott child marriages and called upon young men to marry child widows. Independent India Women in India now participate fully in areas such as education, sports, politics, media, art and culture, service sectors, science and technology, etc. Indira Gandhi, who served as Prime Minister of India for an aggregate period of fifteen years, is the world's longest serving female Prime Minister. The Constitution of India guarantees to all Indian women equality (Article 14), no discrimination by the State (Article 15(1)), equality of opportunity (Article 16), equal pay for equal work (Article 39(d)) and Article 42. In addition, it allows special provisions to be made by the State in favour of women and children (Article 15(3)), renounces practices derogatory to the dignity of women (Article 51(A) (e)), and also allows for provisions to be made by the State for securing just and humane conditions of work and for maternity relief. (Article 42). Feminist activism in India gained momentum in the late 1970s. One of the first national-level issues that brought women's groups together was the Mathura rape case. The acquittal of policemen accused of raping a young girl Mathura in a police station led to country-wide protests in 1979–1980. The protest, widely covered by the national media, forced the Government to amend