Raj and Uddhav Thackeray are marching together in Mumbai today against the Election Commission. Here is an explainer on what the row is about.

At the centre is the Special Intensive Revision (SIR) of electoral rolls. The Election Commission says it is removing duplicate, deceased and ineligible voters. Critics, including the Thackerays, say genuine voters are being struck off and the exercise favours the ruling party.

The Indian Express reported that the Chief Election Commissioner’s two deputies raised concerns about the process 14 times internally. The Commission has said its deliberations are normal and all actions lawful.

The Thackerays accuse the Commission of acting as an extension of the ruling party and of deceiving voters. Their march today runs from Byculla to the BMC headquarters, with participants asked to carry only the Tricolour.

The row has spread: the Congress protested on September 29, the CJP’s October 2 rally led to an FIR against its organisers, and Delhi saw two days of detentions. Chief Minister Fadnavis says allegations should be verified. Trust in the poll body is now the central question.