Businesses are set to get credits for taxes paid in the pre-GST era worth about Rs. 400 crore, with the government set to open a special window for businesses to file their claims from 1 October.With this, businesses that could not avail of credits on central excise duty and VAT at the time of transitioning to GST in 2017, including those who had not filed their claims at that point in time, will get a fresh chance to get their tax credits.