Chandigarh, June 15: Heat wave sweeping most parts of the northern region continued unabated today with mercury at Hisar touching a high of 46.7 degrees Celsius. Ambala recording a maximum of 42.5, the meteorological department said here. Chandigarh experienced another hot day as mercury rose to 41.2 degrees Celsius. Heat wave tightened its grip over most parts of Punjab as Amritsar sizzled at 44.4 degrees Celsius. Ludhiana recorded a high of 42.2 C while Patiala registered 42.5 degrees Celsius. Bureau Report