Nundy's father worked at AIIMS to offer public service to the people and mother had given up her academic career (in History) in London School of Economics and Political Science in order to work set up an organisation for the disabled people in North India. She received a degree in Economics from St. Stephen's College, Delhi University. After a short stint as a TV journalist she studied law at Cambridge University, where she was awarded Emmeline Pankhurst Prize, the Amy Cohen Awards and the Becker Studentship. She later pursued LL.M from Columbia University, New York where she was awarded a Columbia University full-time fellowship.
Nundy worked as a lawyer in New York, international tribunals and the United Nations. She is a lawyer at the Supreme Court in India and the focus of her work is on constitutional law, commercial litigation and arbitration, media law and legal policy. She was described by Forbes Magazine as a "Mind that Matters", by Mint as the "Agent of Change" and by The Times of India as one of the three feminists leading a new wave (the other two being Vrinda Grover and Arundhati Roy).
In 2012, after the Delhi gang rape case, Nundy became increasingly engaged with the anti rape laws and sexual harassment of women in India. There were protests against such a horrific act not only in Delhi but throughout the country and it gained momentum internationally and the recognition that patriarchy plays an important role in the power dynamics between men and women which results in such gruesome acts like rape.
The Verma Committee Report was set up by the government to review India's Anti Rape Laws and Nundy was consulted regarding the report which included all the bills of rights. Even though there was no over all success of this report but one of the victories was that the police officers would be held criminally accountable for reporting acts of sexual violence. However, the government did not refer to the report and hence it led to the passing of Criminal Law (Amendment) Act, 2013- "the anti rape bill."
Nundy, along with other lawyers, is working on a bills of rights for women called the Womanifesto. Despite of all the laws, what she seems to urgently suggest is implementation of a public education program to take down patriarchy since that seems to be a public health concern. According to her marital rape is just rape and hence she wants marital rape to be granted the status of a crime but she sees it as a constitutional issue which is preventing this from happening.
Nundy is one of the few lawyers fighting to seek justice for the victims of the Bhopal Gas tragedy. She was also involved in getting safe water to the communities in these areas and cutting of carcinogenic and chemical filled groundwater and also free healthcare and medical aid to the people there. She challenged the governmental and corporate nexus which was very difficult to breakthrough because of the mounting corruption.
In the case of Shreya Singhal v. Union of India which struck down section 66A of the Information Technology, 2000 (which dealt with issues of freedom of speech and censorship), Nundy appeared on behalf of the People's Union for Civil Liberties (PUCL), an NGO that defends civil liberties and human rights in India.
Nundy's international experience includes commercial arbitration and bilateral investment treaty work, as well as constitutional work. She has helped to draft parts of the interim constitution of Nepal, where she specifically included women’s and children’s rights, conducted workshops with the senate of Pakistan on legislating constitutional rights, and worked with the government of Bhutan on compliance with their international treaties.
Nundy has lent her experience to many talk shows, interactive programs and discussions held on the social media to spread the awareness and uphold the value and dignity of basic rights, a major need of our times.