The plaintiffs seek a declaration under G. L. c. 231A that a zoning amendment adopted by the city council on December 5, 1963, is invalid. The facts are found in a master’s report. The ordinance reclassified *636from Residence C to Business A-l a lot of approximately 19,000 square feet on the corner of Main and State streets
*637in Westfield. It is one of two lots in the block on the south side of Main Street between Taylor Avenue and State Street. The other lot is in the adjacent Business B zone. The effect of the rezoning was to move the boundary line between a business district and a residential district from the middle of the block to the east side of the block at State Street. As shown on the accompanying sketch plan, the easterly boundary of the business district on the north side of Main Street lies somewhat westerly of an extension of the westerly fine of State Street (which does not cross Main Street) but some distance easterly of an extension of the easterly boundary of the Business B district on the south side of Main Street.
The Business A-l zone is a somewhat more restricted zone than the adjacent Business B zone, notably in the specific exclusion of taverns, public garages, gasoline and oil filling stations, automobile sales rooms and used car lots.
The rezoned parcel includes a twelve-room fifty year old dwelling house in which in the past rooms had been rented. It was expensive to heat and the owners had sought unsuccessfully to sell it as a residence. It is “practically indistinguishable” from the house on the adjacent lot in the Business B district which is used as a rooming house. The master found also that it is practically indistinguishable from the house across State Street from the locus which is in the residential zone. The present owners had received an offer for $23,000 for the locus subject to its rezoning for business. The proposal is for the use of the premises as a retail dress shop. The rezoning was voted by the city council after the unanimous approval of the planning board. The board noted that the rezoning would “square off” the existing business area “and would constitute the best use for the property in question.”
Main Street is a principal thoroughfare of the city and as Route 20, it carries traffic from points east and west. The house directly across Main Street from the locus is used for a funeral home. Certain nearby properties in the Residence C zone to the east have nonresidential uses. *638Across State Street, on the south side of Main Street, is a real estate office; on the other side of Main Street are an American Legion post and a fruit stand, respectively 800 and 1,600 feet easterly of the locus. The Residence C district extends roughly one third of the way down State Street embracing three lots on each side of State Street on which the houses are attractive and in good repair. South of these lots the zone is Residence B, a more restricted zone.
That the rezoning was to Business A-l rather than Business B did not make it spot zoning. The new district permitted placing the locus in a business area but with restrictions appropriate to its position as a buffer lot.
There had been changes in the neighborhood which tended to support reconsideration of the zone boundary. The city has grown, traffic on Main Street has increased, and “Main Street, which in the past was almost wholly residential, has become solidly business up to the locus on the west over the past twenty . . . years, and even across the street from the locus . . . [was a] . . . funeral home.” That Main Street to the east had on the whole maintained a predominantly residential character was a counter factor to be weighed but it did not in itself bar reconsideration of the zoning boundary location; so too was the adverse effect on traffic congestion on Main Street because of the additional business premises thereon.1 The city’s planning consultant, working with the planning board, had drawn a master plan which was “filed with the Planning Board for its guidance in 1962. . . . [I]ts transportation map indicated the locus as a part of a ‘proposed central business district.’ The map does not represent the consultant’s thinking . . . [as] he was opposed to the locus as business, but it does represent the Planning Board’s ideas.”
The new location for the easterly boundary of the business district is not inconsistent with good planning. The council *639could have deemed it a better location for that boundary. Leaving in the residence zone one lot on the corner of a main thoroughfare with a business zone beside it and in part opposite it, tended to make that lot unattractive for residential purposes. We assume that the purpose of the original arrangement was to protect State Street as a residential street and to protect the lots to the east on Main Street in their residential use. It could be deemed that this purpose had been achieved at the cost of a less than suitable classification for the locus itself.
The classification is not rendered arbitrary by the change. There is no singling out of one lot for different treatment from that accorded surrounding land indistinguishable from it in character. Lanner v. Board of Appeal of Tewksbury, 348 Mass. 220, 229-230. Because of its location on the corner and adjacent to the business district and because of the character of the uses of nearby properties, the locus is distinguished from the other residential parcels in the Residence C district. Muto v. Springfield, 349 Mass. 479, 482-483, and cases cited.
It is plain that a single appropriate boundary change, consistent with the long range plan, has been adopted at this time at the instigation of the lot owners who will profit therefrom. It cannot be ruled, however, that benefiting them is the sole purpose of the change. Caires v. Building Commr. of Hingham, 323 Mass. 589, 595-596. Raymond v. Commissioner of Pub. Works of Lowell, 333 Mass. 410, 412. Lanner v. Board of Appeal of Tewksbury, supra.
There are sound reasons against accomplishing appropriate zoning changes piecemeal. Nibbling at the edges of established districts tends to remove the protection of the existing zoning ordinance without substituting another overall plan under which hurt to individual properties may be deemed offset or justified by the general advantage. As with the Muto case, supra, this case is only narrowly differentiated from those in which we have ruled a classification invalid. We are unable to rule, however, that the council could not find that it would be reasonably related to public *640convenience and welfare and calculated to encourage the most appropriate use of land throughout the city. Caires v. Building Commr. of Hingham, 323 Mass. 589, 595, 597. Compare Schertzer v. Somerville, 345 Mass. 747, 750-752.
Interlocutory and final decrees affirmed.