The reigning Asian champion was second behind 2013 World Youth Championship gold winner Anita Hinriksdottir of Iceland who ran 2:0054 at the Czech capital last night.
Luka, 27, is still a long way to go as she is placed at 30th spot amomg the season's top list with former world champion and London Olympics silver medallist Caster Semenya of South African leading with 1:56.64, followed by world indoor champion Francine Niyonsaba of Burundi with 1:56.92 and Renelle Lamote of France with 1:58.01.
Luka holds the national record of 1:59.17 which she did way back in 2010. She qualified for Rio Olympics during the World Championships in Beijing last year.
The Kerala runner had clocked 2:02.79 to finish at fourth place at the British Milers Club Grand Prix 2016 at Watford, near London on May 29.