This is an open label phase I study for assessing the safety, tolerance and immunogenicity of 3 escalated doses of the test vaccine, BBV87. The study design has four treatment groups – 3 test groups and a control placebo group with 15 subjects in each group. However, the groups will be divided into three study arms: each arm will have 15 subjects of the test vaccine group and 5 subjects of the placebo group. The randomization will be done in a way that allots 5 subjects of the placebo group to each test dose group. All subjects will be screened (via medical history, physical examination and laboratory investigations) to establish the eligibility criteria. This includes negative antibodies, CHIKV IgG, by ELISA method. The test vaccine and placebo will be administered as 3 doses at 28 days interval on day 1±2, 29±2, and 57±2. Vaccine administration will be performed as an in-patient procedure. Subjects will be admitted in CPU 24 hrs prior to vaccine administration, and will be shifted to MICU for vaccination and observed for 48 hrs; and will be discharged upon completion of all clinical monitoring procedures. Laboratory and biochemical tests will be performed as part of clinical monitoring before discharge, and 24 hrs after vaccine administration. Following vaccination, all participants will be monitored throughout the study period for adverse events with daily telephone contacts (for 7 days after each vaccine, and then weekly), interim clinic visits, subject diary cards, and haematological & biochemical laboratory tests.