(3) Purification
كتاب الطهارة
(3b) Chapter: How to act when relieving oneself - Section 2
(2) باب آداب الخلاء - الفصل الثاني
Mishkat al-Masabih 355 
Mu'adh reported God's messenger as saying, "Guard against the three things which produce cursing:
relieving oneself in watering-places, in the middle of the road, and in the shade.” Abu Dawud and Ibn Majah transmitted it.
وَعَنْ مُعَاذٍ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: " اتَّقُوا الْمَلَاعِنَ الثَّلَاثَةَ: الْبَرَازَ فِي الْمَوَارِدِ وَقَارِعَةِ الطَّرِيقِ وَالظِّلِّ ". رَوَاهُ أَبُو دَاوُد وَابْن مَاجَه
 ضَعِيف  (الألباني)حكم :
Reference : Mishkat al-Masabih 355
In-book reference : Book 3, Hadith 67