Jamnagar ( pronunciation ) is a city located on the western coast of India in the state of Gujarat in the Gulf of Kutch.It is the administrative headquarters of the Jamnagar District. It is the fifth largest city in the state of Gujarat, India, behind Ahmedabad, Surat, Vadodara and Rajkot. Jamnagar is the largest city on the western most side of India.The Modern look of the city was initially given by Jam Saheb Shri Ranjitsinhji, who actual built the city with all the modern infrastructure of that era was done during his reign during 1920s, the city was thereafter substantially developed by Jam Saheb Shri Digvijaysinhji Ranjitsinhji in the 1940s, when it was part of the Princely state of Nawanagar. The city lies just to the south of the Gulf of Kutch, some 337 kilometres (209 mi) west of the state capital, Gandhinagar.World's largest petroleum company, Reliance Industries, has established the world's largest oil refinery near the village of Moti Khavdi in Jamnagar district. The Essar Oil refinery is located in the nearby town of Vadinar.