Imphal, Aug 5 (PTI) Intensifying its protest demanding more autonomy for the hill districts, the All Tribal Students" Union Manipur (ATSUM) began "economic blockades" on two important national highways on Friday, hitting supplies coming from Assam.Several trucks coming from Assam were stranded on the Imphal-Dimapur highway (NH-2) and Imphal-Jiribam highway (NH-39) as protesters blocked the roads with boulders, besides burning tyres, officials said.The ATSUM was demanding the tabling of the Manipur (Hill Areas) Autonomous District Council (Amendment) Bill 2021 in the Monsoon session of the assembly for greater financial and administrative autonomy of the hill region to ensure development at par with the valley areas of the state.Instead, the N Biren Singh-led BJP government of the state introduced the Manipur (hill areas) district council 6th and 7th amendment bills on Tuesday, which the protesters claimed was not in line with their demands.ATSUM was observing a total shutdown in the tribal-dominated hill of Kangpokpi and Senapati since Tuesday after the new amendments were introduced unannounced.Schools, colleges, shops and business establishments were closed because of the shutdown, while passenger buses stayed off the roads. The shutdown ended on Friday morning, following which the "economic blockades" began, affecting supplies to the Meitei-dominated Imphal valley region.Police have arrested five student leaders of ATSUM for "conspiracy" to organise the protests.The monsoon session of the assembly was also adjourned sine die on Friday amid the fiasco.Meanwhile, civic society body Meitei Leepun shut down the Chingmeirong office of the students" body in Imphal, alleging it was targeting the people of the valley through its protests. PTI CORR SOM SOM