Ulhasnagar: Nearly a decade after being shut down in Ulhasnagar over pollution concerns, illegal jeans dyeing units have resurfaced in villages across Kalyan rural, Ambernath and Badlapur, triggering fresh environmental concerns.Environmentalists allege that these units, which use chemical-based dyes and processes to treat denim, are operating clandestinely in villages such as Karole, Usatne and Malangwadi….