As India gets ready to roll out its most ambitious tax system - the Goods and Services Tax or GST - to replace a maze of indirect taxes with an online-based system in less than 10 days, the attention is turning to the IT system that will have to handle tax returns filed by 8 million businesses. "We are confident that our systems are glitch free," says Nabin Kumar, chairman of the GST Network, the organisation that provides the IT backbone to the online tax system. On June 11, West Bengal Finance Minister Amit Mitra had expressed "his apprehensions about the IT preparedness" of GSTN.