New Delhi, Nov 10 The CISF on Friday exempted passengers flying out of Pune, Nagpur, Trichy and Goa airports from getting their hand baggage stamped, a rule introduced decades ago as a security measure. This takes the total number of such airports to 23. "Doing away with stamping of baggage tags has been extended to four more airports," a Central Industrial Security Force (CISF) statement said. The CISF had begun doing away with stamping the hand baggage in December 2016. The 19 earlier airports where this has been implemented in four phases are Delhi, Jaipur, Vadodara, Mumbai, Guwahati, Coimbatore, Hyderabad, Patna, Calicut, Bengaluru, Lucknow, Indore, Ahmedabad, Trivandrum, Bhubaneswar, Kolkata, Chennai, Bagdogra and Cochin. The CISF now plans to do away with the stamping in the remaining 26 airports too where its personnel are deputed. These include Agra, Khajuraho, Dehradun, Jodhpur, Shimla, Kanpur, Bhopal, Port Blair, Bhavnagar, Bhuj, Aurangabad, Shillong, Agartala, Vizag, Gaya, Silchar, Tezpur, Jorhat, Tirupati, Imphal, Raipur, Dimapur and Madurai. The statement said stamping of baggage tags could be dispensed with after certain modifications in the Security Hold Areas of the airports and installation of high-definition CCTV cameras. These modifications were required to make sure passengers could not access bags containing restricted items which are segregated by CISF personnel for checking. "High Definition CCTV cameras focused on the baggage screening system were required so that CISF personnel who cleared a bag could be easily identified to fix accountability," a CISF official said. The official said the system has speeded up security checking. "Earlier, passengers had to get their hand baggage stamped by security staff after the x-ray. The stamp is then checked at the boarding gate. In case of a lapse or loss of bag tag, the passenger has to go back to the security gate, which could potentially lead to missed flights or delays -- both for the passenger and the airline." The practice of stamping hand baggage was introduced in the late 1970s as an anti-hijacking measure. Over time, x-ray machines have made this system superfluous.