Why is Parliament having a debate on Vande Mataram after 150 years?

The debate is part of year-long celebrations marking 150 years of Vande Mataram, with BJP saying it'll highlight key facets. PM Narendra Modi set the stage for discussion, accusing Congress of dropping several stanzas of Vande Mataram in 1937. Congress said Rabindranath Tagore backed limiting to two stanzas, saying Jawaharlal Nehru accepted this as remaining verses were harder to understand.