Complex sentence: This has expanded to a collection which begins on the evening of the 15th of December and ends on Christmas Eve, which covers the whole city centre at any one time there can be over 100 collecters on the street with nearly 1000 taking part in total.
Split into simpler sentences: This has expanded to a collection which begins on the evening of the 15th of December and ends on Christmas Eve, which covers the whole city centre. At any one time there can be over 100 collecters on the street with nearly 1000 taking part in total.