Joint Filing Agreement

                                                                       EXHIBIT 3
                                                                       ---------



                             Joint Filing Agreement

         Pursuant to Rule 13d-1(k)(l)(iii) of Regulation 13D-G of the General
Rules and Regulations of the Securities and Exchange Commission under the
Securities Exchange Act of 1934, as amended, the undersigned agrees that the
statement to which this Exhibit is attached is filed on behalf of each of them
in the capacities set forth below.

Dated:  December 24, 2002


                                        SAIF INVESTMENT COMPANY LIMITED


                                        By: /s/ ▇▇▇▇▇▇ ▇. ▇▇▇
                                            -----------------------------------
                                            Name:  ▇▇▇▇▇▇ ▇. ▇▇▇
                                            Title: Director


                                        SB ASIA INFRASTRUCTURE FUND, L.P.


                                        By: /s/ ▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇
                                            -----------------------------------
                                            Name:  ▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇
                                            Title: Director of SB Asia Pacific
                                                   Investments Limited, which is
                                                   the General Partner of SB
                                                   Asia Pacific Partners, L.P.,
                                                   which is the General Partner
                                                   of SB Asia Infrastructure
                                                   Fund, L.P.


                                        SB ASIA PACIFIC PARTNERS L.P.


                                        By: /s/ ▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇
                                            -----------------------------------
                                            Name:  ▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇
                                            Title: Director of SB Asia Pacific
                                                   Investments Limited, which is
                                                   the General Partner of SB
                                                   Asia Pacific Partners, L.P.


                                        SB ASIA PACIFIC INVESTMENTS LIMITED


                                        By: /s/ ▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇
                                            -----------------------------------
                                            Name:  ▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇
                                            Title: Director





                                        ASIA INFRASTRUCTURE INVESTMENTS LIMITED


                                        By: /s/ ▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇
                                            -----------------------------------
                                            Name:  ▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇
                                            Title: Director


                                        SB FIRST SINGAPORE PTE LTD.


                                        By: /s/ ▇▇▇▇▇ ▇. ▇▇▇
                                            -----------------------------------
                                            Name:  ▇▇▇▇▇ ▇. ▇▇▇
                                            Title: Director


                                        SOFTBANK CORP.


                                        By: /s/ ▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇
                                            -----------------------------------
                                            Name:  ▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇
                                            Title: Attorney-in-Fact of
                                                   SOFTBANK Corp.