Union Minister of State for the Development of Northeastern Region (DoNER) Jitendra Singh on Tuesday said the integrity of India is non-negotiable."The integrity of the Union of India is non-negotiable. I will go back with the slogan that we will ensure that from Meghalaya to Mirpur the integration of India is non-negotiable," Singh told journalists after paying homage to Khasi freedom fighter U. Tirot Sing Syiem from Meghalaya at Hima Nongkhlaw. Hima Nongkhlaw is the erstwhile Khasi state, about 70 km from Meghalaya capital Shillong. Singh said the Modi government is in the process of including in history textbooks the stories of unsung heroes of the Independence struggle from the northeastern states. "In textbooks and other books of reference, we should have adequate references to these unsung heroes who have gone unnoticed," he said.The minister said the Centre is in the process of including the geography, history and tradition and culture of the indigenous people of the northeastern states in National Council of Educational Research and Training (NCERT) textbooks. U Tirot Sing Syiem, a tribal Khasi chief of erstwhile Nongkhlaw state, rebelled against the British Raj in 1829. On January 13, 1833, the British forces treacherously captured him and kept him in captivity at Dhaka, where he died on July 17, 1835.The event was organised to remember the sacrifices made by freedom fighters across India in the context of ten country's Independence Day.