As far as fluoride content in the toothpaste is concerned, it can be upto 1100 ppm. If your children are not eating the paste and using only for cleaning teeth, use of fluoridated toothpaste is safe even in high water fluoride areas. Ahmadabad is not known for high ground water fluoride levels but many parts of Gujarat are. You can check the ground water fluoride levels with ground water authority in the city. If it is higher than 1 ppm then you need to defluorinate the water before using for drinking purpose.