NEW DELHI - A new wave of violent sand and thunder storms hit northern India Sunday killing more than 40 people and leaving widespread disruption, authorities said. At least 18 people were killed by hail and thunder storms that brought down walls, trees and power pylons in Uttar Pradesh state. The deaths came just 10 days after a sand storm left more than 130 dead in the same region. Another 12 people were killed Sunday by thunderstorms in West Bengal, nine by lightning bolts in Andhra Pradesh and two in the capital New Delhi, where winds of more than 100 kilometres an hour forced 70 flights to be diverted.