Agartala, January 10 (IANS): Northeast India's first 100-feet High Mast National Flag (HMNF) was on Wednesday installed in Tripura capital Agartala. Tripura Chief Minister Manik Sarkar unveiled the High Mast National Flag in front of Ujjayanta Palace -- the former royal palace of Tripura and now NE's biggest museum. State-owned Oil and Natural Gas Corporation (ONGC) and New Delhi-based Fast Track Engineering Company jointly installed the HMNF at a cost of Rs 15.89 lakh. "The HMNF was installed first time in northeast India. In and around 300 places across the country such HMNFs were installed by various organisations to popularise the tri-colour. This is ONGC's fifth HMNF in India," an ONGC spokesman said. The official said that the National Flag of 20x30 feet size on a 100-feet-high flag pole become an added attraction of the bordering capital city. "Industrialist Navin Jindal initiated the scheme in India and faced nine-year legal hurdles to get government permission to set up the HMNF in various places of north India," the official added. The flag pole has been designed keeping in mind the geometry of Ujjayanta palace, which was constructed between 1899 and 1901.