At least eight people were killed in a major pile-up in foggy conditions on a northern India highway on Monday, police said.

Around a dozen vehicles crashed in low visibility in Haryana state's JHajar region, leaving eight more injured, area police chief Seema said.

‘A trailer at high-speed rammed into a jeep carrying locals which caused the pile-up. Eight people, including seven women, all passengers of the jeep, died in the crash,’ said Seema, who uses only one name.

Local television footage showed wrecked cars being removed from the road and people pulled out of mangled vehicles.

The pile-up caused a two-kilometre long traffic jam on the highway.

In recent days, heavy fog has engulfed northern India which is experiencing a cold snap. Poor visibility has disrupted transport in the region, delaying air and train traffic.