Right to know whether my phone is being tapped

Right to Privacy is guaranteed under Article 21 of Constitution of India. Unless a State interest like national security etc. is involved, the State cannot snoop on your private communication. You must be knowing about the practical situation in this country, many unconstitutional things are being done these days by many quarters since there is no punishment or practical accountability of government servants. You can try doing an RTI with BSNL and see what they say.