Which of the following in not a fundamental duty?

Yes, it is not a fundamental duty to follow all religious norms under all circumstances.

The Fundamental Duties of the Indian Constitution are a set of civic and moral obligations that are applicable to Indian citizens. Some examples of Fundamental Duties include:

Respecting the Constitution, National Flag, and National Anthem

Cherishing the ideals that inspired India's struggle for freedom

Promoting harmony and brotherhood among all people of India

Renouncing practices that are derogatory to women

Preserving the rich heritage of Indian culture

Protecting the natural environment

Developing scientific temper, humanism, and the spirit of inquiry and reform

The Fundamental Duties are listed in Article 51A of the Indian Constitution. The Swaran Singh Committee recommended the Fundamental Duties in 1976, and the 42nd Amendment Act of 1976 added them to the Constitution. The 86th Amendment Act of 2002 added the 11th Fundamental Duty