Tomato prices have been rising in the city’s retail market for over a week. Heavy rain in major tomato-producing States caused a slump in the arrivals at the Koyambedu wholesale market in Chennai. The Koyambedu market received only 40-50 lorry loads of tomatoes on Wednesday as against the usual quota of 80-90 lorry loads. P. Sukumar, treasurer, Koyambedu Vegetables, Fruits …