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In India , Anti-Terrorism Squads (ATS) are special counterterrorism units present in several state police agencies of India including Maharashtra Police, Gujarat Police, Kerala Police, Uttar Pradesh Police, Rajasthan Police, Bihar Police, Jharkhand Police ,Tamil Nadu Policeand Madhya Pradesh Police.These units are frequently involved in the investigative, intelligence and emergency response aspects related to terrorism and cooperate with other branches of their police departments, police forces from other states, and national agencies such as the Intelligence Bureau and the National Investigation Agency.
The first Anti-Terrorism Squad of India was founded in Maharashtra in 1990 by the then Additional Commissioner of Police, Mumbai Aftab Ahmed Khan (popularly known as A.A. Khan). He was inspired by the Los Angeles Police Department's Special Weapons & Tactics (SWAT) team's methods to combat modern-day terrorism. Since then Anti-Terrorism Squads have been integrated into the police departments of numerous states, with the original ATS of Maharashtra Police being terminated and then reconstituted.
The ATS was formed in December 1990 and helped reduce the crime rate in Mumbai by 70%. However, there were many human rights violations by the squad, from extreme means of torture to public shootings. Following the 1991 Lokhandwala Complex shootout on 16 November 1991 and many more encounters, the organization was terminated in January 1993. The leader of this program, A.A. Khan, was transferred from his position as the chief of Mumbai's ATD to the IGP (Anti Naxalite division) to Nagpur on 29 January 1993 following the termination of the program. One month later on 12 March 1993 the Bombay blasts occurred, and the crime rate has increased since then.
The Anti Terrorism Squad of Maharashtra Police was later reinstated in the states police department by the Government of Maharashtra, vide G.R. No. SAS-10/03/15/SB-IV, dated 8 July 2004.
By state Edit
Maharashtra Police was the first police department in the country to set up an ATS unit. Although the unit was disbanded in 1993, it was later reinducted in the state's police force in 2004 as a special unit of Maharashtra Police.In 2008 ATS chief Hemant Karkare was killed in the line of duty fighting against terrorists in the 26/11 Mumbai attacks.The Anti Terrorism Squad of Maharashtra Police is frequently involved in combating the intelligence and investigation challenges related to terrorism but not armed anti terror operations , which are usually undertaken by other police units.
Uttar Pradesh Edit
The U.P. created its own Anti Terror Squad in 2007.Although the anti terrorism squad of U.P. generally deals with the intelligence aspects of terrorism it has been stepping up its tactical counterrorism capabilities sinces 2017 with creation of tactical units called Special Police Operations Team (SPOT). 
West Bengal Edit
Kolkata Police had two anti-terrorist squads much before the police forces in Delhi and Mumbai came up with the idea. It is another matter that these two units turned out to be woefully inadequate in tackling modern-day terrorism. By the time, the administration realized this and merged them to set up the Special Task Force (STF).In 2008 ATS/STF, Kolkata Police captured most wanted Indian Mujahideen Co-founder Yasin Bhatkal for a case involving large amounts of fake currency.
- "Kerala train fire: Maharashtra Anti-Terrorism Squad nabs suspect near Ratnagiri". www.telegraphindia.com. Retrieved 6 June 2023.
- Service, Indo-Asian News (22 May 2023). "Gujarat ATS arrests suspected Al-Qaeda terrorist; frames charges against 4 people". The Siasat Daily. Retrieved 6 June 2023.
- "First time since formation, Kerala's anti-terrorism squad gets own posts". English.Mathrubhumi. 11 September 2022. Retrieved 6 June 2023.
- "ATS raids different locations in Uttar Pradesh, detain 70 people over alleged links with PFI". The Hindu. 7 May 2023. ISSN 0971-751X. Retrieved 6 June 2023.
- "Rajasthan ATS, SOG to probe Udaipur railway track blast from November 15". The Hindu. 15 November 2022. ISSN 0971-751X. Retrieved 6 June 2023.
- "Migrant workers attack row: Bihar's anti-terrorism squad makes first arrest in fake videos case - The New Indian Express". www.newindianexpress.com. Retrieved 6 June 2023.
- PTI; ThePrint (16 May 2023). "Gangster Aman Srivastava, wanted in 23 cases, arrested by Jharkhand ATS from Navi Mumbai". ThePrint. Retrieved 6 June 2023.
- "It's official: Tamil Nadu to get Anti-Terrorism Squad". The Times of India. 27 May 2023. ISSN 0971-8257. Retrieved 6 June 2023.
- "Madhya Pradesh ATS carries out searches to nab terror suspect". The Times of India. 28 February 2023. ISSN 0971-8257. Retrieved 6 June 2023.
- "The Anti-Terrorism Squad: Unsung Heroes of Indian Counter-Terrorism". 28 December 2015.[permanent dead link]
- "ANTI – TERRORISM SQUAD" mumbaipolice.maharashtra.gov.in retrieved on 23 January 2019
- "uppolice.gov.in| Official Website of Uttar Pradesh Police | Police Units | Anti Terrorist Squad (ATS) | About Us". uppolice.gov.in. Retrieved 10 June 2023.
- Gupta, Jayanta; Mandal, Caeser (3 December 2008). "No training for anti-terror squad". The Times of India Dec 3, 2008, 00:36 IST. Archived from the original on 23 July 2023. Retrieved 3 December 2008.
- Ghosh, Shamik (23 February 2013). "Kolkata Police had Indian Mujahideen mastermind Yasin Bhatkal". NDTV February 23, 2013 6:15 pm IST. Archived from the original on 24 January 2016. Retrieved 23 February 2013.