Humanitarian and Compassionate Grounds
Although the Immigration Act has strict rules and regulations regarding who may or may not be considered admissible to Canada, the Immigration Act does permit anyone who wishes to be a Landed Immigrant of Canada but does not meet the criteria to apply for Landed Immigrant status based on "Humanitarian and Compassionate Grounds".
There are no hard and fast rules about who may apply it is open for anyone but the criteria is very difficult to meet. In addition, the Immigration Officer that reviews the application has what is called the "power of discretion".
These applications are usually reserved for the applicant who may be the eldest son or daughter of successful applicants for Landed Immigrant status in Canada, who are no longer dependent upon their parents and will be left completely alone in their country of origin when their family immigrates. Or for the de facto family member, someone who has been considered a family member for many years of successsful Landed Immigrant applicants but there is no blood relation.
Another example is the undocumented immigrant that has been living in Canada for several years without status but nevertheless has been able to secure stable employment, learn the language, integrate into Canadian society, establish themselves economically and has what the Immigration Officer considers to be a good reason (remember, power of discretion) why the applicant cannot apply for Landed Immigrant status from abroad.
Although, some people believe this type of application to be the best way to apply or that it may be an easy one, it can be one of the most difficult types of applications to be considered due the fact that the Immigration Officer has the power of discretion and what may be a good reason to you or me it may not be to the Immigration Officer reviewing your application.