Why is Mexico not called a democratic country?

Mexico is an American country, that got independence in 1930, and since then it holds an election every six years.

The election held after every six years was won by a party called Institutional Revolutionary Party (PRI) for every term till 200.

Though opposition parties would contest but could never win.

The election was not held in a transparent manner, many illegal practices were followed. The government employees would attend the party meetings; the media would focus only upon PRI’s activities, the teachers would force the parents to vote for only PRI, the polling booth was mismanaged, sometimes the booth was captured or transferred to another in the last minute.

A democratic country is one where elections are held in a free and fair manner.

Hence, we cannot say that Mexico is a complete democratic nation.