Update on Block B-80 is attached herewith

Hindustan Oil Exploration Company Limited ‘Lakshmi Chambers’, 192, St. Mary’s Road, Alwarpet, Chennai - 600 018. INDIA. Phone: 91 (044) 66229000 ● Fax: 91 (044) 66229011 / 66229012 E-mail: contact@hoec.com ● Website: www.hoec.com CIN: L11100GJ1996PLC029880 August 13, 2026 By Online The Listing Department The Corporate Relationship Department National Stock Exchange of India Ltd., BSE Limited “Exchange Plaza”, Bandra Kurla Complex, 1st Floor, P. Jeejeebhoy Towers, Bandra (East), Mumsbai – 400 051 Dalal Street, Mumbai – 400 001 Stock Code: HINDOILEXP Stock Code: 500186 Dear Sir / Madam, Sub: Submission of information pursuant to Regulation 30 of SEBI (Listing Obligations and Disclosure Requirements) Regulations, 2015 – Update on Block B-80 In furtherance to our intimation dated June 10, 2026, we would like to inform you that in Block B-80 the compression configuration on the Mobile Offshore Processing Unit (“MOPU") have been changed to allow lower suction pressures. The test run of the compressors have been started in this new configuration with partial gas sales. We request you to kindly take our aforesaid submission on record. Yours Sincerely, For Hindustan Oil Exploration Company Limited G. Josephin Daisy Company Secretary & Compliance Officer Registered Office: ‘HOEC HOUSE’, Tandalja Road, Off Old Padra Road, Vadodara - 390 020. INDIA. Phone: 91 (0265) 2330766 ● E-mail: contact@hoec.com ● Website: www.hoec.com