When did the word secularism included in your preamble?

The Word "secularism" was included in the Preamble of the Indian Constitution when it was amended in 1976 through the 42nd Amendment. This amendment emphasized the commitment to secularism as a fundamental principle of the Indian state, ensuring that the government remains neutral in matters of religion and treats all religions equally. Prior to this amendment, the Preamble did not explicitly mention secularism, although the principles were reflected in the Constitution's articles.