Stopping Over at a Place Whilst on Journey

1. If whilst on journey you stopped over at a place and decided to stay there for 15 days or more, then it becomes incumbent to fast. You cannot leave out the fast because now, in terms of the Shariah, you are not a musaafir (traveller).
2. However, if your intention was to stay less than 15 days then not fasting during this period in the place you have stopped over at is not sinful.

(Behshti Zewar)