There are a few reasons behind the renaming of NMML as the Prime Ministers' Museum and Library Society and the dropping of Nehru's name:

• The current government has been criticized for their treatment of Nehru and his legacy. Naming the museum after all Prime Ministers, instead of just Nehru, is seen by some as an attempt to downplay Nehru's contributions.
• The government may want to use the museum as a way to promote other Prime Ministers, such as Modi, and their contributions to India.
• The renaming also reflects a broader trend in the country towards emphasizing Indian leaders and history over Western ideals and figures.
• The government has stated that the changes will also include improving the museum's infrastructure and exhibits to attract more visitors.
• The new name may be seen as more inclusive, and a way to honor all of India's Prime Ministers, not just Nehru.

Overall, there are a variety of factors that may have contributed to the decision to rename the NMML, and these reasons are likely to be debated and scrutinized for some time.