Exhibit 4.31

This Letter Agreement (“Letter”) is entered into on this 24th day of February, 2020 at New Delhi, India: BY AND BETWEEN: Bharti Infratel Limited, a company incorporated under the laws of India, having its registered office at 901, Park Centra Sector – 30, NH - 8, Gurugram, Haryana - 122001, India (hereinafter referred to as “Infratel”, which expression shall, unless it be repugnant to the context or meaning thereof, be deemed to mean and include its successors and permitted assigns); Bharti Airtel Limited, a company incorporated under the laws of India, having its registered office at Bharti Crescent, 1 Nelson Mandela Road, Vasant Kunj, New Delhi – 110070, India (hereinafter referred to as “Airtel”, which expression shall, unless it be repugnant to the context or meaning thereof, be deemed to mean and include its successors and permitted assigns); Nettle Infrastructure Investments Limited, a company incorporated under the laws of India, having its registered office at 3rd Floor, Worldmark 2 Asset 8, Aerocity, NH - 8, New Delhi – 110 037, Delhi, India (hereinafter referred to as “Nettle”, which expression shall, unless it be repugnant to the context or meaning thereof, be deemed to mean and include its successors and permitted assigns); Indus Towers Limited, a company incorporated under the laws of India, having its registered office at Building No. 10, Tower-A, 4th Floor, DLF Cyber City, Gurugram, Haryana-122002 (hereinafter referred to as “Indus”, which expression shall, unless it be repugnant to the context or meaning thereof, be deemed to mean and include its successors and permitted assigns); The entities listed in Annexure A hereto (hereinafter referred to as “Vodafone”, which expression shall, unless it be repugnant to the context or meaning thereof, be deemed to mean and include their successors and permitted assigns); Vodafone International Holdings B.V., a company incorporated in the Netherlands, and having its registered office at Rivium Quadrant 173, 2909 LC Capelle aan den IJssel, the Netherlands (“Vodafone Confirming Party”); and Vodafone Idea Limited, a company incorporated under the laws of India, having its registered office at Suman Tower, Plot No.18, Sector-11, Gandhinagar Gujarat 382011 and its corporate office at 7th Floor, Konnectus, Tower B, Bhavbhuti Marg, Opposite New Delhi Railway Station (Ajmeri Gate Side), New Delhi 110 002, India (hereinafter referred to as “VIL”, which expression shall, unless it be repugnant to the context or meaning thereof, be deemed to mean and include its successors and permitted assigns). Infratel, Airtel, Nettle, Indus, Vodafone and VIL are hereinafter also referred to individually as “Party” and, collectively, as “Parties”. WHEREAS: A. The Parties and the Vodafone Confirming Party executed the Implementation Agreement dated April 25, 2018 (“Implementation Agreement”) to give effect to a scheme of amalgamation and arrangement between Infratel and Indus. Capitalised words and expressions used but not defined herein shall have the same meaning as assigned to them under the Implementation Agreement. B. In terms of the Implementation Agreement, several actions were to be completed by the Long Stop Date for the Transaction to become effective, which included but was not limited to seeking requisite approvals from various Governmental Authorities. The Long Stop Date was defined as the date falling 18 months after the Execution Date, which was conditionally extended until 1

February 24, 2020 (“Extended Longstop Date”) pursuant to letter agreements dated October 24, 2019 (“First Extension Agreement”) and December 24, 2019 (“Second Extension Agreement”, and together with the First Extension Agreement, the “Extension Agreements”) since all approvals had not been received and certain other actions had not been completed. C. Until date since all approvals have not been received, the Parties are of the view that the completion of the Transaction is therefore not possible prior to the Extended Longstop Date. D. The Parties are now agreeing to further extend the Extended Longstop Date, subject expressly to the terms set out in the Extension Agreements. Now therefore the Parties hereby agree as follows: 1. The term “Extended Longstop Date” in the Extension Agreements shall mean April 24, 2020. 2. In Clause 2 of the Second Extension Agreement, reference to “February 24, 2020” shall be, and is hereby replaced with “April 24, 2020”. 3. This Letter shall be read together with, and as a part of, the Implementation Agreement and the Extension Agreements. Except as amended hereby, all of the terms and conditions of the Implementation Agreement and the Extension Agreements shall remain in full force and effect. 4. This Letter may be entered into in any number of counterparts, all of which taken together shall constitute one and the same instrument, but shall not be effective until each Party has executed at least one counterpart. Further, the delivery of a PDF format copy of an executed signature page shall have the same force and effect as the delivery of an originally executed signature page. 5. This Letter shall be effective from February 24, 2020. 6. The provisions of Clauses 14 (Confidentiality), 15 (Announcements), 16.9 (Arbitration) and 16.17 (Governing Law) of the Implementation Agreement shall apply mutatis mutandis to this Letter. [Remainder of this page has been intentionally left blank] 2

In witness whereof, this Letter Agreement has been entered into on the date and year first above written. For and on behalf of Bharti Infratel Limited /_s_/_S_a_m_v_i_d_h_i_R_o_d_h_e Name: Samvidhi Rodhe Title: Company Secretary For and on behalf of Bharti Airtel Limited /_s_/ _P_a_n_k_a_j _T_e_w_a_s_i Name: Pankaj Tewasi Title: Company Secretary For and on behalf of Nettle Infrastructure Investments Limited /_s_/ _S_u_mS_i_n_g_h an Name: Suman Singh Title: Authorised Signatory [Signature Page]

For and on behalf of Al-Amin Investments Limited /_s_/_G_._A. _v_a_n_Nie_k_e_r_k Name: G. A. van Niekerk Title: Director For and on behalf of Asian Telecommunication Investments (Mauritius) Limited /_s_/_G_._A. _v_a_n_Nie_k_e_r_k Name: G. A. van Niekerk Title: Director For and on behalf of CCII (Mauritius), Inc. /_s_/_G_._A. _v_a_n_Nie_k_e_r_k Name: G. A. van Niekerk Title: Director For and on behalf of Euro Pacific Securities Ltd /_s_/_G_._A. _v_a_n_Nie_k_e_r_k Name: G. A. van Niekerk Title: Director [Signature Page]

For and on behalf of Vodafone Telecommunications (India) Limited /_s_/_G_._A. _v_a_n_Nie_k_e_r_k Name: G. A. van Niekerk Title: Director For and on behalf of Mobilvest /_s_/_G_._A. _v_a_n_Nie_k_e_r_k Name: G. A. van Niekerk Title: Director For and on behalf of Prime Metals Ltd /_s_/_G_._A. _v_a_n_Nie_k_e_r_k Name: G. A. van Niekerk Title: Director For and on behalf of Trans Crystal Ltd /_s_/ _G_._A. _v_a_n_Nie_k_e_r_k Name: G. A. van Niekerk Title: Director [Signature Page]

For and on behalf of Omega Telecom Holdings Private Limited /_s_/_P_r_ik_a_n_k_a S_in_g_h Name: Prikanka Singh Title: Director For and on behalf of Telecom Investments India Private Limited /_s_/_P_r_ik_a_n_k_a S_in_g_h Name: Prikanka Singh Title: Director For and on behalf of Jaykay Finholding (India) Private Limited /_s_/_P_r_ik_a_n_k_a_Sin_g_h Name: Prikanka Singh Title: Director For and on behalf of Usha Martin Telematics Limited /_s_/ _P_r_ik_a_n_k_a_Sin_g_h Name: Prikanka Singh Title: Director [Signature Page]

For and on behalf of Vodafone Idea Limited _/s_/_P_a_n_k_a_j _K_a_p_d_e_o Name: Pankaj Kapdeo Title: Company Secretary [Signature Page]

For and on behalf of Indus Towers Limited /_s_/_R_a_j_in_d_e_r_Ku_m_a_r Name: Rajinder Kumar Title: Chief of Legal & Company Secretary [Signature Page]

For and on behalf of Vodafone International Holdings B.V. /_s_/_M. _B_u_c_k_e_rs /_s_/_L_._R_.M._Kra_a_n Name: M. Buckers Title: Director Name: L.R.M. Kraan Title: Director [Signature Page]

Annexure A Vodafone (a) Al-Amin Investments Limited, a company incorporated in Mauritius, and having its registered office at Fifth Floor, Ebene Esplanade, 24 Cybercity, Mauritius (b) Asian Telecommunication Investments (Mauritius) Limited, a company incorporated in Mauritius, and having its registered office at Fifth Floor, Ebene Esplanade, 24 Cybercity, Mauritius (c) CCII (Mauritius), Inc., a company incorporated in Mauritius, and having its registered office at Fifth Floor, Ebene Esplanade, 24 Cybercity, Mauritius (d) Euro Pacific Securities Ltd, a company incorporated in Mauritius, and having its registered office at Fifth Floor, Ebene Esplanade, 24 Cybercity, Mauritius (e) Vodafone Telecommunications (India) Limited, a company incorporated in Mauritius, and having its registered office at Fifth Floor, Ebene Esplanade, 24 Cybercity, Mauritius (f) Mobilvest, a company incorporated in Mauritius, and having its registered office at Fifth Floor, Ebene Esplanade, 24 Cybercity, Mauritius (g) Prime Metals Ltd, a company incorporated in Mauritius, and having its registered office at Fifth Floor, Ebene Esplanade, 24 Cybercity, Mauritius (h) Trans Crystal Ltd, a company incorporated in Mauritius, and having its registered office at Fifth Floor, Ebene Esplanade, 24 Cybercity, Mauritius (i) Omega Telecom Holdings Private Limited, a company incorporated in India under the Companies Act, 1956, and having its registered office at 201-206, Shiv Smriti Chambers, 2nd Floor, 49/A Dr. Annie Besant Road, Worli Naka, Mumbai – 400 018, Maharashtra, India (j) Telecom Investments India Private Limited, a company incorporated in India under the Companies Act, 1956, and having its registered office at 201-206, Shiv Smriti Chambers, 2nd Floor, 49/A Dr. Annie Besant Road, Worli Naka, Mumbai – 400 018, Maharashtra, India (k) Jaykay Finholding (India) Private Limited, a company incorporated in India under the Companies Act, 1956, and having its registered office at 201-206, Shiv Smriti Chambers, 2nd Floor, 49/A Dr. Annie Besant Road, Worli Naka, Mumbai – 400 018, Maharashtra, India (l) Usha Martin Telematics Limited, a company incorporated in India under the Companies Act, 1956, and having its registered office at E-47, Bankra Super Market, Bankra, Howrah – 711 403, West Bengal, India 10