Wikipedia
The first day of November is a holiday in Poland. As many people make journeys to visit the burial places of their relatives, heavy traffic develops and accident statistics peak. Most commercial activity also ceases. Cities set up special bus lines which travel between traffic hubs and cemeteries.
Streets are filled with silent and solemn crowds, and cemeteries glow with thousands of candles, presenting a unique and picturesque scene.
Zaduszki is the main holiday commemorating the dead for Slavic Catholics. Zaduszki celebration occurs on All Saints' Day (November 1) and the Day of the Dead (November 2). All Saints' Day was introduced to Europe in year 998 in Benedictine monasteries, and since the 13th century became officially acknowledged by the Western Church as the day of commemoration of all deceased. In folk understanding, All Saints' Day was viewed as the Eve of the main Commemoration ("Zaduszny") Day (November 2) when most folk customs and rituals took place.
It was believed that during the days of Zaduszki in the autumn, the spirits of deceased relatives visited their old homes by gathering near the windows or on the left side of the main doorway. Eventually, it was believed that as they entered the house, they would warm themselves by the home's hearth and search for the commemoration meal prepared for them. Prior to returning to the Otherworld, the souls went to church for a special nighttime mass by the dead priest's soul. The living were not allowed to watch the dead; those who broke this rule would be punished severely.
The ritual of Zaduszki began with caring for the cemeteries: people tidied the graves of their relatives, decorated them with flowers, lit the candles; a collective prayer for the dead was organized, and concluded with having the priest bless the graves with prayers and holy water. Homeowners in Eastern Poland prepared to meet the dead by cleaning and preparing the house for the visit; covering the floor with sand, leaving the door or window open, moving a bench closer to the hearth. And on this bench, a dish of water, a comb, and a towel were placed, so that the souls could wash themselves and comb their hair.
Women would traditionally bake special bread for souls on the Zaduszki holiday. The bread was brought to the cemetery and given to the poor, children, clerics, or simply left on the graves in a similar vein to modern-day 'trick-or-treating'. Families have traditionally tried to give out as much as possible (in some places, they baked and gave out up to 200–300 buns of bread), believing that this would help to bring in wealth and prosperity.
During Zaduszki days, people followed many taboos: by not working in the field, not doing any important household work, and by not starting a trip. According to Polish beliefs, on Zaduszki Eve, one had to go to bed as early as possible, in order not to distract the dead from celebration of their holiday. The remains of the commemorative dinner were not allowed to be removed from the table until morning; going outside and taking out trash or water were tabooed, as well. All the dogs should remain on their chains that night. If someone needed to take out the trash or pour the water out next to the house, he/she would say a special warning by-word: "Move over, soul, or I'll spill my trash/water on you!" Whitening of the oven or walls of the house was also prohibited, in order not to spray the dead with clay and lime.
Zaduszki is not just celebrated in Poland, but in other Slavic countries, like Serbia, Slovenia, and Slovakia, as well. Comparing this Slavic holiday to All Hallows' Eve celebration in Western Europe, one could see that they are closely linked.
The given information is taken from the Dictionary of Svarog's House (Словарь Дома Сварога)- http://pagan.ru/slowar/z/zadushki8.php