You normally say that the house is opposite the railway station, and not `opposite to’. When you use the word `opposite’ in this manner, you are suggesting that there is something separating the two objects. In this case, it could be that the railway station and your house are separated by a road or a street. Opposite implies that the two buildings are on different sides of the road/street. Similarly, when you say, “Divya’s room is opposite Puja’s”, what you are suggesting is that the two rooms are facing each other; there is a corridor between them.
*The nearest supermarket is opposite the hospital. *The people who live opposite Anand’s house are slightly crazy.