Most of those neighborhoods in bad conditions are inhabited by migrants from the interior, mostly from the former Oriente province, nicknamed "palestinos", coming to the capital seeking better job opportunities and greater availability of consumer goods. Internal migration is a critical factor in the growth of Cuba's capital.
A lot of illegal inhabitants in illegal rented homes and overcrowded. Young people settle into buildings that have been declared uninhabitable, or movie theaters, stores or hotels that have been shut down. As a consequence of this deterioration and huge shortage in housing construction a significant amount of overcrowding has taken place with very negative social consequences. Entire families are often forced to sleep in the same room. It is very common to see what was initially a single family dwelling unit being subdivided into two or three family nuclei. The increasing domestic violence appears to be directly connected with this situation as well as the extremely high divorce rate. Yet, many divorced couples must continue living together, although they marry again, subdividing the already restricted dwelling.
Usually, blackouts have taken place throughout the day, but particularly during the "peak hours", between 5:30 and 9:00 p.m. But this has not only been in Havana; the situation has been similar in other cities along the Island. It is important to point out that there are areas where blackouts do not occur, --important hotels, hospitals and the exclusive residences of the new class in power.
Since Cuba is doing "business" with Venezuela (around 2006) there are less blackouts because of the trade/exchange doctors and nurses versus oil.
A popular measure to find a remedy when electricity is cut off, has been returning to the ancient "oil lamp of the fields" popularly known as "chismosas" made in a very primitive manner: A glass bottle with an empty tube of toothpaste inside, to hold a wick, frequently homemade.
Another more ingenious form of coping with the energy crisis has been the building of "energy plants." These are really sets of batteries (mostly obtained in the underground economy) of different types, and arranged with great ingenuity that can provide electricity at night, at least to see the extremely popular TV soap opera and illumination.