It's a Chinese New Year custom. One the eve, the family gather for a reunion dinner. In cases for people go out of the home town to work, they go home for that. It’s a big logistic issue for place like China from what i heard. Nowadays, in Singapore, many people choose to eat out and necessary on the day of the eve. Partly because many eating places are closed and they rip you off more on the eve. Often, on the the eve, they have restricted hours.