Sea plane routes connecting the various islands of Lakshadweep, Andaman and Nicobar as well as Hyderabad’s Prakasam Barrage with Nagarjunasagar in Telangana are among the routes being offered to airlines under the fourth round of UDAN scheme.The Ministry of Civil Aviation invited bids for 134 routes under the low-cost flying scheme, also known as Ude Desh Ka Aam Nagrik (UDAN), on Friday. Interested players can submit their proposals by February 22.Islands of Agatti, Kavaratti, and Mincoy in Lakshadweep have been offered for bidding. Popular islands of Andaman and Nicobar such as Hutbay, Neil, Long Island,Havelock have also been sought to be connected with sea planes under this round of UDAN.On the request of the State government, the Ministry has also invited interest for connecting Prakasam Barrage over Krishna river with Hyderabad as well as Nagarjunasagar dam in Telangana.Last month, the Ministry awarded 235 routes after the successful completion of the third round of bidding for UDAN routes. Players have six months to commence services. These included unserved airports of Andaman and Nicobar at Campbell Bay, Shibpur, Car Nicobar, and six watedromes at Guwahati River Front and Umrangso Reservoir in Assam, Nagarjuna Sagar dam in Telangana, and Shatrunjay Dam and Statue of Unity in Gujarat.Several airports in the northeast region such as Tezpur, Shillong, Passighat and Aizawl have also been offered again for bidding after 56 routes were withdrawn from Air Deccan and Air Odisha because of their failure to provide regular services.Of the 428 routes awarded to airlines under the first two rounds of bidding, 138 have taken off so far.