Kathmandu, Sept. 10 -- Even as the government is preparing to celebrate Constitution Day with fanfare, its coalition partner-the Samajbadi Party Nepal-has said it will stay away from the celebrations. The third largest party in the federal parliament-Rastriya Janata Party Nepal-has already decided to observe September 20 as a black day.

These are the two Madhes-based parties-earlier known by different names-that had protested against the promulgation of the constitution by the Constituent Assembly in 2015.

These two parties, which run the government in Province 2, have also been demanding an amendment to the constitution.

Four years after the adoption of the constitution, some sections of the society, including Madhesis and Tharus, con...