The country's biggest tax reform was launched at a grand function in Parliament's Central Hall at midnight, and the main opposition party rejected multiple appeals by the government to reconsider its decision and attend.
"Congress Chief Ministers and Finance Ministers in state assemblies and the Congress in Parliament supported the bill. Now they call it a tamasha (drama). This is a political compulsion," Mr Gadkari told NDTV, adding, "They once said GST is their child, now they are criticising their own child."
The Congress has consistently claimed authorship of GST and pointed out that in 2011, Mr Gadkari as BJP president was ready to support this but was stalled by the then Gujarat Chief Minister Narendra Modi and Madhya Pradesh Chief Minister Shivraj Singh Chouhan's objections.
Asked for his reaction to traders protests across the country, Mr Gadkari said it will benefit them and most importantly will raise tax collections for the centre and states "license raj - inspector raj, will close. It is a number one economy and there is no chance for a number two economy. No black money will be coming from that. It is a win-win situation for traders, businessmen, consumers, governments, state governments and centre. "
Congress vice president Rahul Gandhi accused the government of rushing through with a reform with great potential "in a half-baked way with a self-promotional spectacle."
"Unlike demonetisation, GST is a reform that the Congress has championed and backed from the beginning, but like demonetisation, GST is being executed by an incompetent and insensitive government without planning foresight and institutional readiness," Mr Gandhi tweeted, saying the country deserves a GST "that does not put crores of its ordinary citizens, small businesses and traders through tremendous pain and anxiety."
The Congress' many objections to tonight's function include Prime Minister Narendra Modi launching GST and not President Pranab Mukherjee and also that a midnight session in the historic Central Hall of Parliament must be used for more special occasions than launching a reform, pointing out that it has happened only thrice before, all three times to celebrate India's Independence.