The Union Environment Ministry's directive to various thermal power plants in the country to either fall in line or face action has set the alarm bells rising in state electricity boards. Warning the managements of thermal plants against pollution, the ministry has directed them to use coal having 34 per cent. At present, the coal used by most of the plants has an ash content of earby 40 percent and is a major source of pollution in places like Delhi, Bathinda, Ropar etc.