The Essar group is planning to invest Rs 10,500 crore in a special economic zone (SEZ) at Hazira, augment steel manufacturing capacity to nine million tonne and expand its refinery at Vadinar."Our investments in the SEZ at Hazira will be over Rs 10,500 crore," Essar group chairman Shashi Ruia said today.He said the group has been approached by major automobile groups like Nissan and component manufacturers like Manineto to set up facilities at the Hazira SEZ.Ruia also said international petrochemical giants had evinced interest to set up base at its SEZ at Jamnagar.