A thick pollution cloud has been covering Montenegro's town of Pljevlja over the past week, with the environment agency issuing a warning to citizens on Tuesday (Dec 23) to stay indoors due to high concentration of sulphur dioxide in the air.<br /><br />WATCH MORE: https://thestartv.com/c/news<br />SUBSCRIBE: https://cutt.ly/TheStar<br />LIKE: https://fb.com/TheStarOnline
