Why are rival Trinamool Congress factions competing to hold the July 21 Martyrs’ Day Rally? | Explained

The story so far: Since the change of regime in West Bengal after the recently concluded Assembly polls , politics in the State is hinged on who is going to occupy the Opposition space. Despite registering a vote share of 40% and winning 80 seats in the Assembly polls, the Trinamool Congress is facing a rebellion with a majority of MLAs and MPs deciding to part ways with party chairperson Mamata Banerjee.