Chandigarh Police have booked 21 people, including Shiromani Akali Dal (Amritsar) chief Simranjit Singh Mann and his son Emaan Singh Mann, after supporters of the Qaumi Insaaf Morcha (QIM) tried to force their way into the city on Independence Day on Saturday, defying prohibitory orders.According to police sources, protesters attacked policemen and tried to breach multiple layers of barricades during the march towards Punjab Lok Bhawan.Mann allegedly disguised himself as a patient, with his head wrapped in bandages, and sat in an ambulance in a bid to slip past the security cordon near Punjab Lok Bhawan, Sector 6. He was taken into custody along with three others—Dpinder Partap Singh, Gopal Singh and Gurpreet Singh.A case, FIR Number 96, was registered at Police Station North on the complaint of ASI Varinder Singh under Sections 217, 223, 353(1)(b) and 3(5) of the Bharatiya Nyaya Sanhita (BNS) and Section 9 of the Punjab Security of State Act, 1953, police sources said. The FIR alleges that the accused violated orders issued by the District Magistrate and obstructed police personnel at Heera Singh Chowk.His son, Emaan Singh Mann, a resident of Fatehgarh Sahib, was among eight people arrested in a separate case—FIR Number 97, registered at Police Station North under Section 223 of the BNS on the complaint of SI Vivek Kumar—after a large gathering assembled near Punjab Lok Bhawan as part of the march called by the QIM and allied organisations, police sources added.Drones deployed, barricades breachedIn a first for the city, police used drones to drop tear-gas shells on protesters who tried to storm the Mattour barrier on the Sector 51/52 dividing road.According to police sources, the protesters tried to break through the barricades with swords, axes, spears and other weapons while raising slogans demanding the release of Sikh prisoners.A case, FIR Number 137, invoking 12 sections of the BNS, besides provisions of the Arms Act and the Prevention of Damage to Public Property Act, was registered at Police Station Sector 36 against QIM leaders Bapu Gurcharan Singh, Lakha Sidhana, Amitoz Mann, Baljit Singh Khalsa and others.Separately, police intercepted two vehicles at the Sector 7/8 dividing road and arrested nine people, all residents of Ludhiana. Four swords, two from each vehicle, were recovered, police said.A case, FIR Number 106, was registered at Police Station East, Sector 26, under Sections 223 and 3(5) of the BNS and the Arms Act, police sources said.Police maintained tight multi-layer barricading, backed by anti-riot vehicles, water cannons and Rapid Action Force personnel, across the Chandigarh-Mohali border through the day to stop the QIM march towards Punjab Lok Bhawan.The morcha, which has been agitating for the release of Sikh prisoners including Jagtar Singh Hawara, has called for a Punjab Bandh on August 21.Investigation in all four cases is under way, police sources said.