Which article refers to the abolition of titles?

Article 18 of the constitution refers to the abolition of titles and makes the following four provisions in that regard:

• No title, not being a military or academic distinction, shall be conferred by the State 
• No citizen of India shall accept any title from any foreign State 
• No person who is not a citizen of India shall, while he holds any office of profit or trust under the State, accept without the consent of the President any title from any foreign State 
• No person holding any office of profit or trust under the State shall, without the consent of the President, accept any present, emolument, or office of any kind from or under any foreign State Right to Freedom

Further Reading:

• Right to Equality (Articles 14 – 18)
• Fundamental Rights – Articles 12-35