Table 2. Major container types and numbers with pupae found during the wet season base line survey (November–December 2009) in Chennai.

			Intervention						Control
Type of container	Total number of container	Proportion to total containers	Container positive	Proportion to container+ve to total	No. of pupae in positive container	% of all pupae	Total number of containers	Proportion to total containers	Container positive	Proportion of container+ve to total	No. of pupae in positive container	% of all pupae
Cement tank*	73	0.021	19	0.062	366	7.34	58	0.019	22	0.099	431	13.14
Coconut shells	14	0.004	5	0.016	89	1.79	6	0.002	5	0.023	52	1.58
Disused container	156	0.045	87	0.282	1342	26.92	58	0.020	41	0.185	691	21.06
Flower vases	25	0.007	16	0.052	329	6.59	16	0.005	7	0.031	130	3.96
Grinding stone	55	0.016	31	0.101	514	10.31	41	0.014	32	0.144	692	21.09
Plastic/metal drum	260	0.076	63	0.205	1222	24.51	193	0.066	36	0.162	558	17.00
Plastic pot	1434	0.417	17	0.055	205	4.11	1168	0.397	13	0.595	53	1.62
Tyres	24	0.007	21	0.068	279	5.60	14	0.005	13	0.595	166	5.06
Miscellaneous†	1396	0.406	49	0.159	639	12.82	1387	0.472	53	0.239	508	15.48
Total (including all containers	3437		308		4985		2941		222		3281

Notes: *Cement tanks, which were the predominant producers of Aedes pupae, had lost their relative importance after the Corporation (public sector) had treated them with temephos, just before our survey in the wet season.

†Miscellaneous containers recorded were ceramic jar, bowl, bucket, metal containers, mud pot, refrigerator trays, and tree holes.