Attock Refinery Limited (PSX: ATRL) has resumed production at its main crude distillation unit with immediate effect, the company informed the main bourse on Wednesday.Recently some improvement has been observed in the uplifting of High Speed Diesel (HSD). Accordingly, ARL has restarted its main unit, however, the situation is being closely monitored with respect to product demand, the stock filing stated.ATRL is principally engaged in the refining of crude oil. The Company is a subsidiary of The Attock Oil Company Limited, England and its ultimate parent is Coral Holding Limited (a private limited company incorporated in Malta).At the time of filing, the company's scrip at the bourse was Rs. 396.2, up 0.79 percent or Rs. 3.12 with a turnover of 203,336 shares on Wednesday.Source: Pro Pakistani