The calculated distance (air line) between Serchhīp and Chhāgalnāiya is approximately 87 miles respectively 140 kilometers.
By car or train, the actual journey to Chhāgalnāiya is certainly longer, as only the direct route (as the crow flies) between Serchhīp and Chhāgalnāiya has been calculated here.
Air line (approximately)
140 kilometers
75 nautical miles