Explanation:
The Silk Letter Movement ('Tehreek-e-Reshmi Rumal') refers to a movement organised by Deobandi leaders between 1913 and 1920, aimed at gaining Indian independence from British rule by forming an alliance with the Ottoman Empire, the Emirate of Afghanistan and the German Empire.

This plot was uncovered by the Punjab CID with the capture of letters from Ubaidullah Sindhi, one of the Deobandi leaders then in Afghanistan, to Mahmud Hasan Deobandi, another leader then in Hejaz. The letters were written on silk cloth, hence the name.