Bihar Deputy Chief Minister Sushil Kumar Modi will head a five-member grouping of state ministers to look into technical challenges being faced by the GST registration and tax filing portal. The GST Council, the highest decision-making body of the new Goods and Services Tax (GST) regime, had on Saturday decided to form a five-member panel to look into the technical glitches facing GST-Network (GSTN). The GSTN, the information technology (IT) backbone and portal for real-time taxpayer registration, migration, and tax return filing under the GST, had faced downtime when the first deadline for filing of returns approached, forcing the government to extend the last date.