Quince (Cydonia oblonga) is a bush sometimes used by city planners to fill hedges. Therefor your best bet of finding it is to pay attention to hegdes in the city. In the late fall to winter it will produce peer-like fruits with a very distinctive tangy taste to it. They work great as a base for chutney. They are ripe when they turn yellow. A good amount of sugar is required to balance out the acidity of the quince. This chutney works well with any dish that’s served with other types of chutneys.