Yogas that arises when a planet other the Sun occupies 2nd ,12th or both Houses reckoned from the Moon are Sunapha, Anapha and Duradhara respectively. All these are favourable yogas. In the absence of these auspicious yogas, there arises an evil or unfavourable yoga called Kemadruma Yoga. 

However, this yoga does not arise, if the Moon occupies a Kendra or there are planets in the Kendras from the Moon. 

Adverse effects of the Yoga
The great Indian sage Varahamihira explains this yoga in his work, Brihat Jataka in a verse which says: when the Kemadruma is present, the native is dirty, ever wallowing in grief, bereft of wealth and in a lowly position.  He may be a servant or a wicked person. These effects would visit the person even if he were born into a royal family. 

Therefore, it should be understood that Kemadruma Yoga is a Daridra Yoga or a yoga that reduces one into poverty as well. 

Cancels the effects of all other favourable yogas
Meanwhile, Sage Parasara says that malefic Chandra yogas cancel the effects of other yogas and produce their own effects instead. This is the most dreadful aspect of the Kemadruma Yoga.  If the Kemadruma Yoga is present, it would render ineffective all other favourable yogas produced by other combinations say, like Bheri, Mridanga, Amala or any Rajayoga for that matter.  

There are also other combinations that cause Kemadruma Yoga according to the classical work, Jataka Sarvaswa. They are:
When the Moon occupies the Lagna or the 7th House without the aspect of Jupiter.
When the Moon joins the Sun aspected by a debilitated planet and occupies a debilitated Navamsa.
When the birth is in the night time, the 8th House from the Moon is aspected by or occupied by an evil planet.
When the Moon is in conjunction with Rahu and is aspected by a malefic.
There are Kemadruma Bhanga yogas as well. They are as follows:
When the quadrants from the Moon are occupied by planets other than the Sun.

When the Moon is aspected by all other planets
When Tara planets occupy both sides of the Moon’s Navamsa.
One would experience the effects of the Kemadruma Yoga during the Maha Dasa of the Moon and it is noteworthy that the cancellation takes place only in the Dasa periods of the planets causing the cancellation of the Dosha.