As you have asked about the Oil and natural gas Corporation (ONGC), I am giving you information about it, check below for the details

ONGC is a public sector undertaking (PSU).
It was formed in the year 1956.
It’s headquarter is located in Dehradun, Uttarakhand, India.

It offers following products:
Oil Crude
Gas Natural
Naphtha
Liquefied Petroleum Gas
C2/C3 (Ethane/Propane)
Superior Kerosene Oil
Fuel
Mineral Oil
Motor Spirit
High Speed Diesel (Trading)
Propane
Light Diesel Oil
Carbon Credit

ASSETS/ PLANTS:

It has following plants:

1. Mumbai High Asset, Mumbai
2. Neelam & Heera Asset, Mumbai
3. Bassein & Satellite Asset, Mumbai
4. Uran Plant, Uran
5. Hazira Plant, Hazira
6. Ahmedabad Asset, Ahmedabad
7. Ankleshwar Asset, Mehsana
8. Mehsana Asset, Mehsana
9. Rajamundry Asset, Rajamundry
10. Karaikal Asset, Karaikal
11. Assam Asset, Nazira
12. Tripura Asset, Agartala

Contact:
ONGC, Jeevan Bharti,
Tower-II, 124-Indira Chowk,
New Delhi – 110001
Telephone: 011-23317213 (Office), 011-23310729 (Fax)