In old days, people used to have visiting cards with a telephone number with PP written next to it, in India. While I am not sure what this PP actually stands for, but it meant that, the person may not pick up the phone, but can be reached if h/her name was told and asked to come to the phone.
And now days have when, when people carry a mobile phone with multiple SIM cards or multiple Mobile Numbers! With advent and penetration of Mobile phones, getting a personal phone number has become the easiest thing, where most of the time, the SIM card and number can be purchased with less than a dollar in India.
And with low cost Chinese phone with facility to put multiple SIM in single mobile phone, people started carrying multiple mobile number. And even high end Smatphones now a days have facility to put more than one phone, more reason to get multiple mobile numbers!