Basic structure doctrine was given in the Keshvanand Bharati case in 1973. According to it some basic elements of the constitution cannot be amended. Ambit of basic structure is not defined by any rule and regulation. It has been constantly evolving by judicial interpretation. Example of basic structure are secularism, supremacy of the constitution, separation of the power between judiciary, executive and legislature., federal structure etc.
Its relevance can be explain by its origin. It came into existence when 24th Amendment of the constitution empowered parliament to amend any part of the constitution. To restore such imbalance of power basic structure came into existence via judicial pronouncement.
Further it has helped judiciary to give efficient judgements and to decide on cases where according to judiciary parliament has transgress on its power.
It is a turning point in the constitutional history of India. As it tried to settle the tussle going on between judiciary and executive. It ensure that the constitution ideals remain sacrosanct. It put limitation on the power of legislature and executive. It tried to give permanency to the constitution of India.
