The Central Board of Indirect Taxes and Customs (CBIC) has clarified that real estate developers and Resident Welfare Associations (RWAs) will be liable to pay 18% GST on electricity bills if they charge flat owners more than the power tariff set by Discoms. However, if they charge the same amount for electricity as state electricity boards or Discoms, they will be considered 'pure agents' and GST won't apply. According to experts, this ruling may lead to an increase in rental costs.