New Delhi, April 1 -- Election campaign funding in India could make a mud-wrestling pit look clean. This has oft been said. Numbers cited off the record for what it costs to contest a single Lok Sabha seat are in such a wide range that high multi-crore figures have lost their shock value. According to a study by the Centre for Media Studies, this year's general elections would see as much as Rs.50,000 crore being spent, up 40% over the 2014 polls. For decades, donations to parties and candidates had largely been in cash, often from shadowy sources, raising grave questions of political integrity. In 2017, however, the Bharatiya Janata Party-led government started a much-vaunted "clean up" exercise by changing the official rules on corporate donations and introducing electoral bonds. Both these measures are under fire now that the Election Commission has filed an affidavit at the Supreme Court against the shroud of opacity they have placed on the funding of political parties....