ISLAMABAD (Israr Khan) Pakistan’s major oil refineries on Thursday signed long-pending upgrade agreements, kicking off an investment program worth nearly $6 billion. The program aims to modernize the country’s aging refining sector, produce cleaner Euro 5 standard fuel and strengthen energy security. Attock Refinery Limited, National Refinery Limited, Synergico Pakistan Limited and Pakistan Refinery Limited have signed these agreements, while Pakistan’s largest refinery Parco is also expected to sign the agreement soon.