sherry chan has more. >> these yellow sign are erywhere across taipei. they show the locations and the capacity of thousands of air raid shelters where people can hide in case of an attack. now, this shows a real-time map so users can find the nearest shelter. officials want residents to get familiar with these spots and even basements of private properties. >> this is one of the many car parks in the city. >> that is a problem. efficacy groups say many of these shelters are very poorly equipped. >> they are worried about a reliable access to these shelters. >> many basements are oupied. they might be used as a storage space and they are not properly maintained or could even be blocked. >> what will happen in the worst case scenario if china attacks? these shelters are different from what many people expect. >> they are supposed to provide temporary protection when an airstrike occurs. missile attacksre usually over a veryhort tim three to four minutes. they might also go on for a couple of hours. facilities such as ventilation or drinking water supplies