New Delhi, July 2 -- Former finance minister Arun Jaitley on Monday said with the increase in revenue the country may effectively have two rates for the GST. He, however, ruled out a single slab GST saying that such a system is possible only in "extremely affluent" countries where there are no poor people. "As revenue increases further, it will give an opportunity to policy makers to possibly merge the 12% and 18% slab into one rate, thus, effectively making the GST a two rate tax," he said in his blog 'Two Years After GST'....