BEIJING -- Commercial housing sales in Beijing fell 19.8 percent year-on-year to 3.89 million square meters in the first half of the year, the city's bureau of statistics said Wednesday.

The sluggish sales came as city authorities moved to cool off the property market with a ban on mortgage loans for third homes, higher lending rates and purchase restrictions.

In February, it unveiled rules to prohibit home purchases by non-local registered families who have no proof of social security or income tax payments in the city for five straight years.

It also prohibited new home purchases by Beijing families who own two or more apartments, and non-Beijing registered families who own at least one apartment.

Amid other efforts to curb home price rises, the city government also invested more in affordable public housing.

The total investment on affordable housing amounted to 27.9 billion yuan ($4.3 billion) in the first half of the year, up 2.3 times year-on-year, the bureau said in a statement

New affordable housing reached 6.55 million square meters in floor area, an increase of 3.1 times from the same period last year, according to the statement.