Four Bills related to the Goods and Services Tax or GST will be debated in the Lok Sabha or lower house of Parliament today, as the government pushes to meet a July 1 launch date for the unified tax regime that subsumes a slew of indirect taxes at the centre and in states. Seven hours have been allotted for today's debate, which is likely to begin at noon today, with union minister Arun Jaitley speaking first. For the Congress, former union minister M Veerappa Moily will be first speaker.