Two other persons who were standing nearby when the incident happened also sustained injuries when Pankaj Soni and his partner Sonu Soni allegedly flung the corrosive substance on Ashok Kumar Jain and his son Atul, they said.
"The accused were having a running dispute with their landlord over vacating his shop," said in-charge of City Kotwali police station A Dubey.
After a heated exchange of words, the accused who use acid in their jewellery business, threw it at Ashok and Atul while some of it also fell on Pradeep Singh and Sanjeev Soni, both the customers present at the shop, police said.
A case has been registered against the duo and a search is on to trace them.