NEW DELHI  - The Indian govt is unlikely to call a snap election despite its biggest ally abruptly quitting the ruling coalition, as it needs time to implement flagship welfare schemes and hopes the economy will improve, government sources said. The withdrawal of the Dravida Munnetra Kazhagam has rattled markets, which are worried that it has left PM Manmohan Singh unable to pass reforms needed to turn around the worst economic slowdown in a decade. That, in turn, has fired speculation that the govt, which is in a minority in parliament and relies on the support of powerful but unpredictable regional parties to stay in power, could call a quick election before its term officially runs out next year.