Calcutta, Jan.24 :    Calcutta, Jan.24:  The Calcutta-Dhaka bus service appears to be on the verge of collapse, thanks to illegal operators who run private vehicles till the Petrapole border. The bus service was flagged off on July 9, 1999. Waiting for passengers on the other side - Benapole - are private buses registered in Bangladesh. Besides charging less than the official bus operators, the private ones provide a faster service too. The unauthorised Sumo brigade, the vehicle mostly used on the Indian side, causes a daily foreign exchange loss of Rs 1.2 lakh to the Central government, besides a daily Rs 2-lakh loss incurred by the state government by way of sales tax and royalty on the route charged from bus operators. At 5 am every day, a fleet of about 40 Sumos, each carrying 10 passengers, leaves for Petrapole border from Marquis Street and from the L20 bus stand at Esplanade. The official operators have drawn the attention of transport minister Subhas Chakraborty and West Bengal Surface Transport Corporation managing director Shantanu Goswami to these illegal operators. 'We have to refund about Rs 2 lakh to Bangladeshi passengers in Dhaka every month as, during the return journey, they prefer to take the 'break service' offered by the Sumo operators,' said an accountant of Basanti Travels & Tours, official operators of Souhardya, the bus service from Calcutta. Since losses are mounting, the alternative is to withdraw the service. A more serious issue was raised by an Intelligence Branch officer in North 24 Parganas. He said it had now become easy for Pakistani ISI agents to reach Calcutta by this Sumo service. 'After arriving at Benapole by bus, passengers wanting to avail of the Sumo service go in a group to the immigration and Customs office,' the officer said. 'An officer then leads the group through a 15-minute process, during which money changes hands, passports are stamped and the passengers cleared.' The procedure is repeated on the Indian side by an Indian officer, the IB man added. Passengers from Bangladesh have to carry at least $200 when they come to India. This condition is illegally bypassed when the Sumo service is taken. The price of the bus ticket for the Calcutta-Dhaka-Calcutta journey is Rs 1,000. These air-conditioned coaches are 40-seaters. Hence, only 80 Bangladeshis can enter India by road daily (except for Sunday, when there is no service). But actually, more than 2,000 Bangladeshis enter India on the illegal service.